XSAMS: XML Schema for Atomic, Molecular and Solid Data

Version 0.1.1 Draft Document, January 14, 2011

This version: http://www-amdis.iaea.org/xsams/docu/v0.1.1.pdf Latest version: http://www-amdis.iaea.org/xsams/docu/ Previous versions: http://www-amdis.iaea.org/xsams/docu/v0.1.pdf

Editors: M.L. Dubernet, D. Humbert, Yu. Ralchenko Authors: M.L. Dubernet, D. Humbert, Yu. Ralchenko, E. Roueff, D.R. Schultz, H.-K. Chung, B.J. Braams Contributors: N. Moreau, P. Loboda, S. Gagarin, R.E.H. Clark, M. Doronin, T. Marquart

Abstract This document presents a proposal for an XML schema aimed at describing Atomic, Molec- ular and Particle Surface Interaction Data in distributed databases around the world. This general XML schema is a collaborative project between International Atomic Energy Agency (Austria), National Institute of Standards and Technology (USA), Universit´ePierre et Marie Curie (France), Oak Ridge National Laboratory (USA) and Paris Observatory (France). Status of this document It is a draft document and it may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use this document as reference materials or to cite them as other than “work in progress”.

Acknowledgements The authors wish to acknowledge all colleagues and institutes, atomic and molecular database experts and physicists who have collaborated through different discussions to the building up of the concepts described in this document.

Change Log

Version 0.1: June 2009 Version 0.1.1: November 2010 Contents

1 Introduction 11 1.1 Motivation...... 11 1.2 Limitations...... 12

2 XSAMS structure, types and attributes 13 2.1 Atomic, Molecular and Particle Surface Interaction Data XML Schema Structure 13 2.2 Attributes ...... 16 2.2.1 units...... 16 2.2.2 stateID...... 16 2.2.3 sourceRef ...... 16 2.2.4 methodRef...... 16 2.2.5 functionRef ...... 16 2.2.6 computerLanguage ...... 16 2.3 SimpleTypes ...... 17 2.3.1 DataDescriptionType ...... 17 2.3.2 ReferenceFrameType ...... 17 2.3.3 AngularMomentumType...... 17 2.3.4 AngularMomentumProjectionType ...... 17 2.3.5 ElementSymbolType...... 17 2.3.6 PrincipalQuantumNumberType ...... 17 2.3.7 ParityType...... 17 2.3.8 MixingClassType ...... 18 2.3.9 OrbitalMomentumSymbolType ...... 18 2.3.10 StateRef...... 18 2.4 ComplexTypes ...... 18 2.4.1 PrimaryType...... 18 2.4.2 DataType ...... 18 2.4.3 ValueType...... 19 2.4.4 ParameterType ...... 19 2.4.5 OrbitalAngularMomentumType ...... 19 2.5 ChemicalElementType...... 20

3 Sources 21 3.1 SourcesType...... 21 3.2 SourceType ...... 21 3.2.1 sourceID...... 23 3.2.2 CategoryType ...... 23 3.2.3 SourceName...... 23 3.2.4 Year ...... 23 3.2.5 Authors ...... 23 3.2.6 Other optional parameters for data sources ...... 24 4 States.Particles 25 4.1 ParticleType ...... 25 4.1.1 ParticleNameType...... 25 4.2 ParticlePropertiesType...... 26

5 States.Solids 27 5.1 SolidType ...... 27 5.2 MaterialType...... 28 5.3 MaterialCompositionType ...... 28 5.4 MaterialComponentType ...... 28

6 States.Atoms 31 6.1 Introduction ...... 31 6.2 Atoms ...... 31 6.3 AtomType ...... 31 6.4 IsotopeType ...... 32 6.5 IsotopeParametersType ...... 32 6.6 IonStateType ...... 33 6.7 AtomicStateType ...... 34 6.7.1 AtomicNumericalDataType ...... 34 6.7.2 AtomicQuantumNumbersType ...... 35 6.8 AtomicCompositionType ...... 36 6.8.1 AtomicComponentType ...... 36 6.8.2 SuperConfigurationType...... 37 6.8.3 SuperShellType ...... 37 6.9 ConfigurationType...... 38 6.9.1 ConfigurationType.ConfigurationLabel ...... 38 6.9.2 AtomicCoreType...... 38 6.9.3 ShellsType...... 38 6.9.4 ShellType ...... 39 6.9.5 ShellPairType ...... 39 6.10TermType ...... 40 6.10.1 LSCouplingType...... 40 6.10.2 jjCouplingType ...... 41 6.10.3 J1J2CouplingType...... 41 6.10.4 jKCouplingType ...... 41 6.10.5 LKCouplingType...... 42 6.10.6 TermLabel...... 42

7 States.Molecules 43 7.1 Molecules ...... 43 7.2 MoleculeType ...... 43 7.3 MolecularChemicalSpeciesType ...... 44 7.3.1 MolecularChemicalSpeciesType.OrdinaryStructuralformula ...... 44 7.3.2 ChemicalSpeciesType.StoichiometricFormula ...... 45 7.3.3 MolecularChemicalSpeciesType.IonCharge ...... 45 7.3.4 MolecularChemicalSpeciesType.ChemicalName ...... 45 7.3.5 MolecularChemicalSpeciesType.IUPACName ...... 45 7.3.6 MolecularChemicalSpeciesType.URLFigure ...... 45 7.3.7 MolecularChemicalSpeciesType.InChI ...... 45 7.3.8 MolecularChemicalSpeciesType.InChIKey ...... 45 7.3.9 MolecularChemicalSpeciesType.CASRegistryNumber ...... 46 7.3.10 MolecularChemicalSpeciesType.CNPIGroup ...... 46 7.3.11 MolecularChemicalSpeciesType.MoleculeNuclearSpins ...... 46 7.3.12 MolecularChemicalSpeciesType.StableMolecularProperties ...... 46 7.4 MolecularPropertiesType ...... 46 7.4.1 MolecularPropertiesType.MolecularWeight ...... 46 7.4.2 MolecularPropertiesType.OtherProperties ...... 46 7.5 MoleculeNuclearSpinsType ...... 46 7.5.1 AtomArrayType...... 47 7.5.2 AtomNType...... 47 7.5.3 BondArrayType...... 47 7.5.4 BondType...... 48 7.6 MolecularStateType ...... 49 7.6.1 MolecularStateType.stateID...... 49 7.6.2 MolecularStateType.Description ...... 50 7.6.3 MolecularStateType.MolecularStateCharacterisation ...... 50 7.6.4 MolecularStateType.TotalSpinMomentumS ...... 50 7.6.5 MolecularStateType.Parity ...... 50 7.6.6 MolecularStateType.TotalMagneticQuantumNumberS ...... 50 7.6.7 MolecularStateType.ElectronicHome ...... 50 7.7 MolecularStateCharacterisationType ...... 50 7.7.1 MolecularStateCharacterisationType.StateEnergy ...... 51 7.7.2 MolecularStateCharacterisationType.TotalStatisticalWeight ...... 51 7.7.3 MolecularStateCharacterisationType.NuclearStatisticalWeight . . . . . 51 7.7.4 MolecularStateCharacterisationType.NuclearSpinSymmetryType . . . . 51 7.7.5 MolecularStateCharacterisationType.Lifetime ...... 51 7.7.6 MolecularStateCharacterisationType.Parameters ...... 52 7.8 ElectronicHomeType...... 53 7.9 ElectronicComponentType ...... 53 7.9.1 ElectronicComponentType.Description...... 53 7.9.2 ElectronicComponentType.SerialQuantumNumber ...... 53 7.9.3 ElectronicComponentType.MixingCoefficient ...... 53 7.9.4 ElectronicComponentType.ElectronicCharacterisation...... 54 7.9.5 ElectronicComponentType.TotalMolecularProjectionL ...... 54 7.9.6 ElectronicComponentType.VibrationalHome ...... 54 7.10 ElectronicCharacterisationType...... 54 7.10.1 ElectronicComponentType.TermSymbol ...... 54 7.10.2 ElectronicComponentType.Configuration ...... 54 7.10.3 ElectronicComponentType.Conformation ...... 54 7.10.4 ElectronicComponentType.SymmetryGroup ...... 55 7.11 VibrationalHomeType ...... 55 7.11.1 ElectronicHomeType.Polyad ...... 55 7.11.2 ElectronicHomeType.VibrationalComponent ...... 55 7.12 VibrationalComponentType ...... 55 7.12.1 VibrationalComponentType.Description ...... 56 7.12.2 VibrationalComponentType.SerialQuantumNumber ...... 56 7.12.3 VibrationalComponentType.MixingCoefficient ...... 56 7.12.4 VibrationalComponentType.VibrationalCharacterisation...... 56 7.12.5 VibrationalComponentType.VibrationalQuantumNumbers ...... 56 7.12.6 VibrationalComponentType.RotationalHome ...... 56 7.13 VibrationalCharacterisationType ...... 57 7.13.1 VibrationalCharacterisationType.VibrationalSpeciesNotation ...... 57 7.13.2 VibronicCharacterisationType.VibronicSpeciesNotation ...... 57 7.14 VibrationalQuantumNumbersType ...... 57 7.14.1 VibrationalQuantumNumbersType.VibrationalNu ...... 57 7.14.2 VibrationalQNType.TotalVibrationL ...... 57 7.14.3 VibrationalQuantumNumbersType.VibronicAngularMomentumK . . . . 57 7.14.4 VibrationalQuantumNumbersType.VibronicAngularMomentumP . . . . 58 7.15 RotationalHomeType ...... 58 7.15.1 RotationalHomeType.RotationalCharacterisation ...... 58 7.15.2 RotationalHomeType.RotationalComponent ...... 58 7.16 RotationalCharacterisationType ...... 59 7.16.1 RotationalCharacterisationType.RoVibrationalSpeciesNotation . . . . . 59 7.16.2 RotationalCharacterisationType.RoVibronicSpeciesNotation ...... 59 7.16.3 RotationalCharacterisationType.RoVibronicAngularMomentumP . . . . 59 7.16.4 RotationalCharacterisationType.PermutationSymmetry...... 59 7.16.5 RotationalCharacterisationType.InversionSymmetry...... 59 7.17 RotationalComponentType ...... 60 7.17.1 RotationalComponentType.MixingCoefficient ...... 60 7.17.2 RotationalComponentType.SerialQuantumNumber ...... 60 7.18 DiatomAndLinearPolyatomicType ...... 60 7.19 LinearNoElecNoHyperFType ...... 61 7.19.1 LinearNoElecNoHyperFType.TotalAngularMomentumN...... 61 7.19.2 LinearNoElecNoHyperFType.TotalMagneticQuantumNumberN. . . . . 61 7.20 LinearNoElecHyperFType ...... 61 7.20.1 LinearNoElecHyperFType.TotalAngularMomentumN ...... 61 7.20.2 LinearNoElecHyperFType.HyperfineQuantumNumbers ...... 61 7.21 HyperfineQuantumNumbersType ...... 61 7.21.1 HyperfineQuantumNumbersType.TotalAngularMomentumF ...... 62 7.21.2 HyperfineQuantumNumbersType.TotalMagneticQuantumNumberF . . 62 7.22 HyperfineCouplingISum ...... 62 7.22.1 HyperfineCouplingISum.ISum ...... 62 7.22.2 HyperfineCouplingISum.IntermediateHyperfineQuantumNumber . . . . 62 7.23 LinearElecCouplingType ...... 62 7.23.1 LinearElecCouplingType.Description ...... 63 7.23.2 LinearElecCouplingType.EfSymmetry ...... 63 7.24HundCaseAType...... 63 7.25HundCaseBType...... 64 7.26 HyperfineCaseAAlpha ...... 64 7.27 HyperfineCaseABeta...... 64 7.28 HyperfineCouplingHundCaseB ...... 64 7.29 NonLinearPolyatomicType...... 65 7.30 NonLinearNoElecNoHyperFType ...... 65 7.30.1 NonLinearNoElecNoHyperF.TotalMagneticQuantumNumberN . . . . . 65 7.31 NonLinearNoElecType...... 66 7.31.1 NonLinearNoElec.TotalAngularMomentumN ...... 66 7.31.2 NonLinearNoElec.MolecularProjection ...... 66 7.31.3 NonLinearNoElec.C2Symmetries ...... 66 7.32 NonLinearNoElecHyperFType ...... 66 7.33 NonLinearElecNoHyperFType ...... 66 7.34 NonLinearElecHyperFType ...... 67 7.35 NonLinearElecCouplingType...... 68 7.36 RoVibronicSplittingType...... 68 7.37 MolecularProjectionType ...... 69 7.37.1 MolecularProjectionType.TotalMolecularProjectionN ...... 69 7.37.2 MolecularProjectionType.AsymmetricProjection ...... 69 7.37.3 MolecularProjectionType.HinderedMotion ...... 69 7.38 C2SymmetriesType ...... 70 7.39 CharacterisationType ...... 70 7.40 MixingCoefficientType...... 70 7.41SymbolType ...... 71 7.42 MolecularQuantumNumberType ...... 72 7.43 ComplexMolecularQuantumNumberType ...... 72 7.43.1 ComplexMolecularQuantumNumberType.modesType ...... 74 7.43.2 vibrationLNu-i ...... 74 7.43.3 ComplexMolecularQuantumNumberType.vibrationSymmetry ...... 74 7.43.4 ComplexMolecularQuantumNumberType.vibrationInversion...... 74 7.43.5 ComplexMolecularQuantumNumberType.vibrationSymmetryIndex . . . 74 7.43.6 ComplexMolecularQuantumNumberType.nuclearSpinRefs2 ...... 74 7.43.7 ComplexMolecularQuantumNumberType.nuclearSpinRef ...... 74 7.43.8 ComplexMolecularQuantumNumberType.spinSumRef ...... 74 7.43.9 ComplexMolecularQuantumNumberType.electronicSpinRef...... 75 7.43.10 ComplexMolecularQuantumNumberType.quantumNumberRef . . . . . 75

8 Processes and Processes.Radiative 77 8.1 ProcessesType...... 77 8.2 Processes.Radiative ...... 77 8.3 RadiativeType ...... 77 8.4 RadiativeTransitionType...... 78 8.5 EnergyWavelengthType ...... 78 8.6 WavelengthWavenumberType...... 79 8.7 RadiativeTransitionProbabilityType ...... 80 8.7.1 TransitionProbabilityA ...... 80 8.7.2 OscillatorStrength ...... 80 8.7.3 LineStrength...... 81 8.7.4 WeightedOscillatorStrength ...... 81 8.7.5 Log10WeightedOscillatorStrength ...... 81 8.7.6 IdealisedIntensity ...... 81 8.7.7 Multipole ...... 81

9 Processes.NonRadiative 83 9.1 NonRadiativeType...... 83 9.2 NonRadiativeTransitionType ...... 83 10 Processes.Collisions 85 10.1 CollisionalTransition ...... 85 10.1.1 ProcessClass...... 86 10.1.2 ReactantsTypeandProductsType ...... 87 10.1.3 Threshold ...... 87 10.2 DataSetsandDataSet...... 88 10.2.1 FitData ...... 89 10.2.2 TabulatedData...... 90

11 Methods 95 11.1Method ...... 95

12 Functions 97 12.1Function...... 97 12.2Expression ...... 99 12.3Y...... 99 12.4Arguments...... 99 12.5ArgumentType...... 99 12.6Parameters...... 100 12.7Parameter ...... 100 12.8ReferenceFrame ...... 101 12.9Description...... 101 12.10SourceCodeURL ...... 101

A List of Atomic Elements 103 A.1 Introduction ...... 103 A.2 Isotopicatomicspecies ...... 103 A.3 ListofElementsinAtomicNumberOrder ...... 103

B List of quantum numbers and symmetry identifications 109 B.1 Noteforintermediatecoupling ...... 109 B.2 Note for notations of quantum angular momenta for molecules ...... 109 B.3 Quantumnumbers...... 109 B.3.1 nuclearSpin ...... 109 B.3.2 Parity ...... 109 B.3.3 SerialQuantumNumber ...... 109 B.3.4 AsymmetricTau ...... 110 B.3.5 AsymmetricKa...... 110 B.3.6 AsymmetricKc...... 110 B.3.7 AsymmetricTau ...... 110 B.3.8 TotalSpinMomentumS ...... 110 B.3.9 TotalMagneticQuantumNumberS ...... 110 B.3.10 TotalMolecularProjectionS ...... 110 B.3.11 TotalMolecularProjectionL ...... 110 B.3.12 TotalAngularMomentumN ...... 111 B.3.13 TotalMagneticQuantumNumberN ...... 111 B.3.14 TotalMolecularProjectionN ...... 111 B.3.15 TotalAngularMomentumJ ...... 111 B.3.16 TotalMagneticQuantumNumberJ ...... 111 B.3.17 TotalMolecularProjectionJ ...... 111 9

B.3.18 TotalAngularMomentumF...... 111 B.3.19 TotalMagneticQuantumNumberF ...... 112 B.3.20VibrationNu ...... 112 B.3.21VibrationLNu ...... 112 B.3.22TotalVibrationL ...... 112 B.3.23 VibronicAngularMomentumK ...... 112 B.3.24 VibronicAngularMomentumP ...... 112 B.3.25 RovibronicAngularMomentumP ...... 112 B.3.26 HinderedK1,HinderedK2 ...... 112 B.4 Symmetries ...... 113 B.4.1 PermutationSymmetry ...... 113 B.4.2 EfSymmetry ...... 113 B.4.3 C2aSymmetry ...... 113 B.4.4 C2bSymmetry ...... 113 B.4.5 C2cSymmetry ...... 113 B.4.6 VibrationalSpeciesNotation ...... 113 B.4.7 VibronicSpeciesNotation ...... 113 B.4.8 RoVibrationalSpeciesNotation...... 113 B.4.9 RoVibronicSpeciesNotation ...... 113

C Description of couplings for molecular Physics 115 C.1 Coupling of Rotation and Electronic motion in diatomic molecules ...... 115 C.1.1 Hund’scase(a) ...... 115 C.1.2 Hund’scase(b) ...... 116 C.2 Coupling Schemes for Magnetic Hyperfine Structure (diatomic molecules other than 1Σ ...... 116 C.2.1 Case (aα) ...... 117 C.2.2 Case (aβ) ...... 118 C.2.3 Case (bβN ) ...... 119 C.2.4 Case (bβS)...... 120 C.2.5 Case (bβJ )...... 121 C.3 Exampleofhyperfinecouplingbytwonuclei ...... 121

D List of the XSAMS Process Codes 123 D.1 Introduction ...... 123 D.2 ProcessCodes...... 123 D.2.1 AtomicandMolecularCollisions ...... 124 D.2.2 ParticleSolidInteractions ...... 125 D.2.3 CombinationofProcesses...... 125

E List of the IAEA DCN codes 127 E.1 StructureandSpectra...... 127 E.2 Electron-Heavy-Particle Interactions ...... 128 E.3 Photon-Particle and Field-Particle Interactions ...... 129 E.4 Heavy-ParticleInteractions ...... 130 E.5 Particle-MatterInteractions ...... 131 E.6 DataCompilations...... 132 E.7 Bibliography...... 132 10 11

Chapter 1

Introduction

1.1 Motivation

Many fields in astronomy, physics, energy production and industry depend on databases for atomic, molecular and particle-surface interaction processes (AMPSI). A reliable exchange of such data has been recognized as important for decades, and the Atomic and Molecular (A+M) Data Unit of the International Atomic Energy Agency established a Data Centre Network (DCN) in 1976 to address this vital issue in connection with fusion energy research (Lorenz and Seamon (1977)). Thus, the ALADDIN data exchange system was adopted in 1988 by the DCN for use by the fusion community in a variety of applications (Janev (1988)). While developments in data exchange within the fusion community were deemed to be adequate two decades ago, a rapid expansion of the Internet resulted in an equally impressive expansion of electronic databases. Most DCN members maintain separate databases, each with a distinct interface and data formats. Independently, the ADAS project was initiated in support of the JET programme (ADAS (2009)), and the resulting system has developed into a large project with a dedicated internal method of data exchange. Until recently, difficulties were experienced in obtaining the underlying AMPSI data from ADAS without being a member of the group. Furthermore, the astrophysics community has its own set of dedicated databases and interfaces. Under these circumstances, there is clearly an urgent need for a new data exchange standard based on the latest technology. The International Virtual Observatory Alliance (IVOA) undertook some initial work from 2002 onwards to define and adopt an XML schema for data exchange (Hanisch (2002)). There have been other formats for AMPSI data exchange involving selected data producers and databases, but they did not include global efforts to define a data exchange process. During the course of the 2004 ICAMDATA meeting in Japan, group discussions focused on the need to develop a more comprehensive schema for AMPSI data for general use. This group consisted of Yu. Ralchenko of the National Institute of Standards and Technology (USA), D. Schultz of the Oak Ridge National Laboratory (USA), M.L. Dubernet of Universit´ePierre et Marie Curie (France) and E. Roueff of the Observatoire Paris-Meudon (France), and D. Humbert and R.E.H. Clark of the International Atomic Energy Agency (Austria), and they have met twice every year to develop such a schema. Recently, P. Loboda and S. Gagarin have joined the group from the All-Russian Institute of Technical Physics, Russia. Summary reports of the meetings are available as IAEA reports and can be downloaded from the A+M Unit web site (XSAMS (2002)). The resulting XML Schema for Atoms, Molecules and Solids (XSAMS) is described in this document, along with a proposal to adopt XSAMS as a new standard for the exchange of AMPSI data. The primary objective of the XSAMS exchange standard is to set up a framework for the correct exchange of AMPSI data, rather than to exchange correct data. Important issues such as data verification and data quality are not addressed by XSAMS, which has been established solely as the data exchange procedure. Although XSAMS does require inclusion of documentation of the source and generation of the data, issues related to the correctness or applicability of the data are left for consideration by data producers. 12 Chapter 1. Introduction

The overall structure of XSAMS consists of specifying physical processes in terms of states. Specific rules are used to describe the physical states of atoms, molecules, ions, elementary particles and solids as unambiguously as possible. States can be specified in any of a number of levels of detail and in different coupling schemes. Processes between states can be described using a reference to initial and final state, as well as a process type. The numerical data for processes can be tabulated, or parameters for a fitting procedure with provision for specifying the exact nature of the fitting function. Different types of differential cross sections as well as total cross sections can be accommodated. Finally, since the origin and history of the data are necessary for data assessment, XSAMS imposes strict requirements on the traceability of the data, with the mandatory inclusion of information on data sources and the methods used to generate specific sets of data. XSAMS was developed through the joint efforts of researchers from the International Atomic Energy Agency (Austria), National Institute of Standards and Technology (USA), Oak Ridge National Laboratory (USA), Universit´ePierre et Marie Curie and Observatoire Paris-Meudon (France), with contributions from the All-Russian Institute of Technical Physics (Russia). The schema for describing states of physical systems and processes connecting different states are detailed in the following sections. All required and optional entries are clearly described, and examples given.

1.2 Limitations

As of January 14, 2011, some parts of the schema are well developed (e.g., on atomic and molecular structure or collisions) while the others are only in the initial phase of development (e.g., solids). It was nevertheless decided to add those less-advanced sections in order to provide some insight into future development of the schema. 13

Chapter 2

XSAMS structure, types and attributes

2.1 Atomic, Molecular and Particle Surface Interaction Data XML Schema Structure

The XSAMS schema provides a framework for a structured presentation of AMPSI data in an XML file. It is based on the physical representation of interaction between various objects through description of the physical states and interaction characteristics. Therefore, XSAMS provides rules for presentation of (i) states of atoms, molecules, solids (surfaces) and some elementary particles, (ii) characteristics of interaction between physical objects, and (iii) sources of the data. 14 Chapter 2. XSAMS structure, types and attributes

An XSAMSData object is defined by the type XSAMSDataType which in turn may consist of 6 elements:

• Mandatory element States of type StatesType which may include sub-elements Atoms (Sec. 6), Molecules (Sec. 7), Solids, Particles. 2.1. Atomic, Molecular and Particle Surface Interaction Data XML Schema Structure 15

• optional element Processes of type ProcessesType.

• mandatory element Sources of type SourcesType.

• optional element Methods of type Methods.

• optional element Functions of type Functions.

• optional element Comments of type xs:string containing any additional relevant infor- mation not decribed in other elements.

The elements and attributes of XSAMS are described in detail below. 16 Chapter 2. XSAMS structure, types and attributes

2.2 Attributes

There are several attributes that are used throughout the schema.

2.2.1 units Type: xs:token. Can take a value from the list of units relevant to AMPSI (Table Ta- ble 2.1). This list will updated and extended as necessary with the goal of using the UnitsML approach (http://unitsml.nist.gov). The positive powers are indicated by digits, the neg- ative powers follow the backslash symbol /. Examples: eV/amu, cm2, kg.m/s2. For unitless (dimensionless) parameters, use unitless.

Table 2.1: List of allowed units as of January 14, 2011 eV/amu keV/amu MeV/amu eV keV MeV au 1/cm J Ry cal K kJ/mol kcal/mol Hz kHz MHz m cm nm A˚ deg rad srad s m3/s cm3/s cm6/s m2 cm2 b Mb 1/s W C.m J/T C.m2 m/s cm/s C electron g amu kg g 1/m2/s 1/cm2/s J/m2/s J/cm2/s 1/m2 1/cm2 J/m2 J/cm2 W/m2 W/cm2

2.2.2 stateID Type: xs:ID. Identifier for a particular state (atoms, molecules, etc.). Composed of the upper-case letter S followed by one or more symbols.

2.2.3 sourceRef Type: xs:IDREFS. Reference to one or more sourceID elements describing bibliographic sources. Each of the references must be an upper-case letter B followed by one or more symbols.

2.2.4 methodRef Type: xs:IDREFS. Reference to one or more methodID elements describing specific methods of data production. Each of the references must be an upper-case letter M followed by one or more symbols.

2.2.5 functionRef Type: xs:IDREFS. Reference to one or more functionID elements describing functions used for data presentation. Each of the references must be an upper-case letter F followed by one or more symbols.

2.2.6 computerLanguage Type: xs:string. Name of a computer language used for presentation of a particular expres- sion or formula. Examples: fortran or C++. 2.3. Simple Types 17

2.3 Simple Types

2.3.1 DataDescriptionType Type: xs:token. Descriptor for the type of a collisonal parameter 2.3:

• crossSection

• rateCoefficient

• collisionStrength

• probability

• effectiveCollisionStrength

• sputteringYield

• sputteredEnergyCoefficient

• particleReflectionCoefficient

• energyReflectionCoefficient

• meanPenetrationDepth

2.3.2 ReferenceFrameType Type: xs:string. Descriptor for the frame of reference:

• CenterOfMass

• LaboratoryFrame

• TargetFrame

2.3.3 AngularMomentumType Allowed values: non-negative integer or half-integer. Examples: 11.5, 2, 2.0, 0.5.

2.3.4 AngularMomentumProjectionType Allowed values: integer or half-integer. Examples: -11.5, 2, +2.0, -0.5.

2.3.5 ElementSymbolType Allowed values: an upper-case letter that may be followed by a lower-case letter. Examples: D, Hf, P.

2.3.6 PrincipalQuantumNumberType Allowed values: positive integer.

2.3.7 ParityType Allowed values: even, odd, undefined. 18 Chapter 2. XSAMS structure, types and attributes

2.3.8 MixingClassType

Indicates the nature of the mixing coefficients in the expansion of a wave function in a specific basis. Allowed values: squared and signed.

2.3.9 OrbitalMomentumSymbolType

Allowed values: a lower-case letter. Examples: s, f.

2.3.10 StateRef

Type: xs:IDREF. A reference to a stateID (see 2.2.2). Composed of an upper-case letter S followed by one or more symbols.

2.4 Complex Types

2.4.1 PrimaryType

This is the fundamental elementary type used to built other types as extensions. It contains the optional attributes sourceRef (see 2.2.3) and methodRef (see 2.2.4) as well as the optional element Comments.

2.4.2 DataType

Extension of the PrimaryType which is used for description of numerical data including units and accuracy. Contains a mandatory element Value of type ValueType and an optional element Accuracy of type xs:string. 2.4. Complex Types 19

2.4.3 ValueType

The data must be of type xs:double with the mandatory attribute units (see 2.2.1).

2.4.4 ParameterType

Type: xs:string. Used for presentation of parameters used in, e.g., fitting functions. Con- tains a mandatory element Name of type xs:token and an optional element Description of type xs:string.

2.4.5 OrbitalAngularMomentumType

Represents an orbital angular momentum as a mandatory non-negative integer Value and an optional lower-case letter Symbol (example: p). 20 Chapter 2. XSAMS structure, types and attributes

2.5 ChemicalElementType

The mandatory element NuclearCharge must be a positive integer. The optional element ElementSymbol must begin with an upper-case letter which may be followed by a lower-case letter. Examples: P, T, Au. 21

Chapter 3

Sources

The Sources part of XSAMS describes the sources of data, i.e., journal articles, books, pro- ceedings, personal communications, etc. The data sources described here are then referred to in other parts of an XML document by their references (see below).

3.1 SourcesType

The element Sources is of type SourcesType that contains one or more elements Source each of type SourceType.

3.2 SourceType

This type describes a data source. 22 Chapter 3. Sources 3.2. SourceType 23

3.2.1 sourceID

Type: xs:ID. This attribute assigns a unique ID to each data source. Must begin with the upper-case letter B followed by one or more characters (e.g., B33hf). sourceID is then referred to with the attribute sourceRef (see 2.2.3).

3.2.2 CategoryType

Type: xs:string. Describes types of data sources. Allowed values as of January 14, 2011:

• book

• journal

• preprint

• private communication

• proceedings

• database

• report

• theses

3.2.3 SourceName

An xs:string containing the name of a journal, proceedings, book, etc. Example: Physical Review A, PhysRevA, PRA, Proceedings of the 10th Conference on something.

3.2.4 Year

Type: xs:gYear. Example: 2009

3.2.5 Authors

Unordered list of authors, each belonging to AuthorType which contains a mandatory Name of type xs:string and optional Address of type xs:string. 24 Chapter 3. Sources

3.2.6 Other optional parameters for data sources Include Title of type xs:string, Volume of type xs:string, DigitalObjectIdentifier of type xs:token, PageBegin (i.e., initial page) of type xs:string, PageEnd of type xs:string, UniformResourceIdentifier of type xs:anyURI, Publisher of type xs:string, City of type xs:string, ProductionDate of type xs:date, Version of type xs:string. A list of Editors (each of type xs:string) can be provided as well. 25

Chapter 4

States.Particles

Describes a number of elementary particles, namely, electron, photon, muon, and positron, if such a description is essential for a particular process. An example can be provided by photoionization.

4.1 ParticleType

If a particle is needed, then it must have a stateID (see 2.2.2). The attribute name of the type ParticleNameType is optional.

4.1.1 ParticleNameType Type: xs:string. Name of an elementary particle from the following list:

• photon

• electron 26 Chapter 4. States.Particles

• muon

• positron

4.2 ParticlePropertiesType

Describes optional properties of an elementary particle such as ParticleCharge (type xs:integer), ParticleMass (type DataType), ParticleSpin (type AngularMomentumType), and ParticlePolarization (type AngularMomentumProjectionType). 27

Chapter 5

States.Solids

The States.Solids part of XSAMS that describes properties of solids and surfaces is still in the inital phase of development. However, it was decided to provide at least such rudimentary description in order to give users and developers a clear idea of the chosen approach.

5.1 SolidType

Extension of the PrimaryType. Attribute stateID is mandatory. Must have one or more elements Layer of type MaterialType. 28 Chapter 5. States.Solids

5.2 MaterialType

The material is defined here as a uniform macroscopic part of a solid. It is characterized by the mandatory parameters MaterialName (type xs:string) and MaterialComposition (type MaterialCompositionType), and optionally by MaterialThickness (type DataType), MaterialTopology (type xs:string), and MaterialTemperature (type DataType). Cur- rently, MaterialTopology can only be described by a string.

5.3 MaterialCompositionType

Extension of the PrimaryType. Must have one or more elements Component, each belonging to the MaterialComponentType.

5.4 MaterialComponentType

Characterized by ChemicalElement (of ChemicalElementType, see 2.5) and either StoichiometricValue or Percentage, both of which are of type xs:decimal. All these parameters are mandatory. 5.4. MaterialComponentType 29 30 Chapter 5. States.Solids 31

Chapter 6

States.Atoms

6.1 Introduction

This section describes static properties of atoms and atomic ions such as state energy, total angular momentum, composition of the wave function with mixing coefficients, etc.

6.2 Atoms

The element Atoms is of type AtomsType which is an extension of PrimaryType containing one or more elements Atom of type AtomType.

6.3 AtomType

AtomType is an extension of PrimaryType containing element ChemicalElement of type ChemicalElementType and one or more elements Isotope of type IsotopeType. 32 Chapter 6. States.Atoms

6.4 IsotopeType

IsotopeType defines a sequence containing an optional element IsotopeParameters of type IsotopeParametersType, one or more elements IonState of type IonStateType, and an optional parameter Comments of type xs:string.

6.5 IsotopeParametersType

IsotopeParametersType is an extension of PrimaryType. The mandatory integer element MassNumber is the total number of nucleons (protons plus neutrons). Optional elements include Mass of type DataType and NuclearSpin of type AngularMomentumType. 6.6. IonStateType 33

6.6 IonStateType

IonStateType is an extension of PrimaryType containing a mandatory integer element IonCharge, optional element IsoelectronicSequence of type ElementSymbolType, and one or more elements AtomicState of type AtomicStateType. 34 Chapter 6. States.Atoms

6.7 AtomicStateType

AtomicStateType is an extension of PrimaryType containing mandatory attribute stateID (type xs:ID) and optional elements AtomicNumericalData of type AtomicNumericalDataType, AtomicQuantumNumbers of type AtomicQuantumNumbersType, and AtomicComposition of type AtomicCompositionType.

6.7.1 AtomicNumericalDataType

An extension of the PrimaryType that may contain the following elements: StateEnergy (above the ion ground state), IonizationEnergy, LandeFactor, QuantumDefect, TotalLifeTime, Polarizability, and StatisticalWeight. All these elements but the latter are of type DataType. The statistical weight of a free atom/ion is an integer, however, in a plasma it can become non-integer and therefore here StatisticalWeight is assumed to be a real number. 6.7. AtomicStateType 35

6.7.2 AtomicQuantumNumbersType

Represents quantum numbers of an atomic state. Parity is of type ParityType, TotalAngularMomentum, relativistic parameter Kappa and HyperfineMomentum belong to the type AngularMomentumType, and MagneticQuantumNumber is of type AngularMomentumProjectionType. 36 Chapter 6. States.Atoms

6.8 AtomicCompositionType

Extension of the PrimaryType. Contains components of the atomic wavefunction in a specific basis. Each element Component is of type AtomicComponentType.

6.8.1 AtomicComponentType

Describes individual components of the atomic wavefunction in a specific basis. May contain elements Superconfiguration (type SuperconfigurationType), Configuration (type ConfigurationType), Term (type TermType), MixingCoefficient (type MixingCoefficientType) and Comments. 6.8. AtomicCompositionType 37

6.8.2 SuperConfigurationType

Contains one or more list of elements Supershell (type SupershellType), that is, electron distribution over atomic supershells.

6.8.3 SuperShellType

Describes how many electrons populate a specific supershell characterized by a positive-integer principal quantum number n. The element NumberOfElectrons of type xs:double can be non-integer to take into account possible plasma effects. The element PrincipalQuantumNumber is of type xs:positiveinteger. 38 Chapter 6. States.Atoms

6.9 ConfigurationType

Describes how electrons are distributed over nl shells. May contain optional elements AtomicCore (type AtomicCoreType), ConfigurationLabel and a list of Shells (type ShellsType).

6.9.1 ConfigurationType.ConfigurationLabel

This element (of type xs:string) is used to represent configuration in a condensed form, if necessary. For instance, one may prefer to make use of a short configuration label 2s2.2p instead of providing details of shell populations etc.

6.9.2 AtomicCoreType

Used to compactly represent the atomic core. For instance, one may prefer to use notation [Ne]3d to describe the excited configuration 1s22s22p63d in a Na-like ion. In this case, it would be sufficient to only indicate the ElementCore element, which will be Ne.

6.9.3 ShellsType

The shells in a configuration can be represented both individually and in terms of shell pairs. 6.9. ConfigurationType 39

6.9.4 ShellType As an atomic shell is typically represented as nlw, all three parameters PrincipalQuantumNumber n, OrbitalAngularMomentum l, and NumberOfElectrons w are mandatory. NumberOfElectrons may be a non-integer decimal number in order to reflect plasma effects. Other optional parame- ters include Parity (type ParityType), TotalAngularMomentum (type AngularMomentumType), relativistic parameter Kappa (κ of type AngularMomentumType), ShellTerm (type TermType) and an optional attribute shellID (type xs:ID).

6.9.5 ShellPairType ShellPairType describe a coupled pair of atomic shells. In addition to descriptors for each of the shells, it contains the mandatory attribute shellPairID to be referenced in a document. 40 Chapter 6. States.Atoms

6.10 TermType

Currently an atomic term can be represented in five coupling schemes, i.e., LS, jj, J1J2, jK, and LK. For a detailed description of these and other schemes see, e.g., Atomic Spectroscopy at http://physics.nist.gov/Pubs/AtSpec/index.html.

6.10.1 LSCouplingType

Describes LS-coupling in an atomic term in terms of total angular orbital momentum L (type OrbitalAngularMomentumType) and total spin S (type AngularMomentumType). Optional 6.10. TermType 41 element Multiplicity is defined as 2S +1 and therefore always is a positive integer. Optional element Seniority is a non-negative integer with an optional attribute soureceRef.

6.10.2 jjCouplingType

Describes jj-coupling in an atomic term as two or more j-values (each of AngularMomentumType).

6.10.3 J1J2CouplingType

Describes J1J2-coupling in an atomic term as two or more j-values (each of AngularMomentumType). Similar to the jj-coupling.

6.10.4 jKCouplingType

Describes jK-coupling in an atomic term typical in, e.g., noble-gas-like ions. The K quantum number is mandatory, while the core momentum j and the spin of outer electron(s) S2 are optional; each of them is of AngularMomentumType. 42 Chapter 6. States.Atoms

6.10.5 LKCouplingType Describes LK-coupling (or LS ) in an atomic term in terms of atomic core angular momentum 1 −→ −→ −→ L and its sum with the total spin of the core: K= L + S1. The spin of outer electron(s) S2 is an optional element of type AngularMomentumType.

6.10.6 TermLabel This element (an xs:string) is used to represent an atomic term in a condensed form, if necessary. For instance, one may prefer to make use of a term label 3P instead of separately indicating the term S and L values. 43

Chapter 7

States.Molecules

7.1 Molecules

The element Molecules is of type MoleculesType which is an extension of PrimaryType and which contains one or more elements Molecule of type MoleculeType.

7.2 MoleculeType

MoleculeType is an extension of PrimaryType. It provides all information on molecular chem- ical species through MolecularChemicalSpecies of type MolecularChemicalSpeciesType and one or more elements MolecularState of type MolecularStateType. These molecular species may be involved in various processes that are described in the Processes section. 44 Chapter 7. States.Molecules

7.3 MolecularChemicalSpeciesType

The object MolecularChemicalSpeciesType describes a simple model to identify the chem- ical molecule involved in the description of States and Processes.

NOTE: Recommendations on Organic and Biochemical Nomenclature, Symbols and Ter- minology are available on the International Union of Pure and Applied Chemistry (IUPAC)1 webpage.

7.3.1 MolecularChemicalSpeciesType.OrdinaryStructuralformula It is of type ReferencedTextType. Standard formula describing the chemical complex written in Latex (molecule or molecular ion). For the time being, the ordinaryStructuralformula element can not be used for search, because a worldwide consensus among molecular physicists is not reached yet. Nevertheless some guidelines must be provided in order to uniquely identified the chemical species.

• For simple molecules involving several atoms, the formula should reflect the order of the

1http://www.chem.qmul.ac.uk/iupac/ 7.3. MolecularChemicalSpeciesType 45

chemical bonds involved. For isotopic atomic components of the formula, the above rule applies.

• When one or several radicals, such as methyl, CH3, are involved, they should be indicated in bracket followed by the number of their occurence as a lower subscript. They are placed in the formula following the order of the chemical bonds. Sometimes the formula of the radical is replaced by an alias such as (Me) for methyl or (Et) for ethyl.

• The conformation (cis, trans, etc ...) should be indicated before the part of the formula giving the various atomic components.

• For more complex molecules, no general rules are provided for now in the document and any string describing the molecule can be used.

• Molecular ions should be described by their chemical formula followed by a plus/minus sign and the number of charges (when different from one). For example, the dyazenylium + molecular ion would be $N 2H^ +$ (N2H ) and the carbonyl doubly charged ion $CO^ {2+}$ (CO2+).

7.3.2 ChemicalSpeciesType.StoichiometricFormula For molecules it is constituted by an alphabetical suite of the atomic constituents followed by the total number of their occurence (purely ASCII). For example: CH2O2 (CH2O2) corre- sponding to formic acid whose formula are $t/c-HCOOH$ (t/c − HCOOH). This is useful for a primary search of resources.

7.3.3 MolecularChemicalSpeciesType.IonCharge Type: xs:integer. It gives the charge of the molecular ion. Examples: +1 or -1

7.3.4 MolecularChemicalSpeciesType.ChemicalName It is of type ReferencedTextType, i.e. a string (with reference) giving the name of the chemical complex. The name element can not be used for search, but rather for information because different names might be associated to a single chemical complex.

7.3.5 MolecularChemicalSpeciesType.IUPACName It is of type ReferencedTextType,i.e. a string (with reference) giving the IUPAC name. It can be used for search.

7.3.6 MolecularChemicalSpeciesType.URLFigure Provides an URL to a figure showing the molecule in its stable configuration.

7.3.7 MolecularChemicalSpeciesType.InChI Provides the InChI number. It is of type ReferencedTextType.

7.3.8 MolecularChemicalSpeciesType.InChIKey Provides the InChIKey number. It is of type ReferencedTextType. 46 Chapter 7. States.Molecules

7.3.9 MolecularChemicalSpeciesType.CASRegistryNumber Provides the CAS Registry Number. It is of type ReferencedTextType.

7.3.10 MolecularChemicalSpeciesType.CNPIGroup It is of type SymbolType and describes the Complete Nuclear Permutation Inversion Group.

7.3.11 MolecularChemicalSpeciesType.MoleculeNuclearSpins It is of type MoleculeNuclearSpinsType. It describes the position of the nuclear spins in the molecule. This is a simple description extracted from the XMLCore Schema. The identification of nuclear spins is used in the hyperfine description of the molecular states.

7.3.12 MolecularChemicalSpeciesType.StableMolecularProperties Element StableMolecularProperties is of type MolecularPropertiesType which pro- vides information on properties of the molecule.

7.4 MolecularPropertiesType

7.4.1 MolecularPropertiesType.MolecularWeight The molecular weight can be calculated as the sum of the individual isotopic masses of all the atoms in any molecule. It is of type DataType.

7.4.2 MolecularPropertiesType.OtherProperties Describes other properties of the chemical complex and is of type CharacterisationType.

7.5 MoleculeNuclearSpinsType

The MoleculeNuclearSpinsType assigns nuclear spins to atoms in the molecule. It contains information on atoms with AtomArray of type AtomArrayType and on bonds with BondArray of type BondArrayType. 7.5. MoleculeNuclearSpinsType 47

7.5.1 AtomArrayType

Contains one or more elements AtomN of type AtomNType.

7.5.2 AtomNType

AtomNType is derived from PrimaryType with additional attributes nuclearSpinId (identifies the atom or the nuclear spin associated to this atom. It is composed of the upper-case letter Q followed by one or more symbols), elementSymbol of type ElementSymbolType (gives the element as described in Appendix A), isotope (is a positive integer giving the isotope num- ber), nuclearSpin of type AngularMomentumType (gives the nuclear spin), hydrogenCount (integer giving the number of hydrogens attached to this element, it is recommended to use hydrogenCount when the hydrogens do not take part in the assignation of nuclear spins), count (integer giving the number of times the element appears).

7.5.3 BondArrayType

Contains one or more elements Bond of type BondType. 48 Chapter 7. States.Molecules

7.5.4 BondType Has 3 attributes: atomRefs2 of type xs:IDREFS which points to the two atoms of the bond (as defined in AtomArray), order (xs:string) that can take values S, D, T or a user definition. 7.6. MolecularStateType 49

7.6 MolecularStateType

Formally a MolecularState element of type MolecularStateType is characterized by a single eigenvalue (possibly degenerate) and a single eigenstate (when non degenerate eigenvalue) of the hamiltonian describing the energy structure of the chemical compound. When the eigenvalue is degenerate, the quantum numbers associated to the degeneracy are not provided. The eigenvalue corresponds to the StateEnergy, and is given relative to an energyOrigin. The eigenstate is characterized by a set of good quantum numbers, such as parity and total angular momemtum, and described by a wavefunction often expanded over some basis func- tions. The expansion is characterized by a coupling scheme between the quantum numbers identifying individual basis functions. Each component of the expansion is described in the ElectronicComponent, VibrationalComponent, RotationalComponent objects.

7.6.1 MolecularStateType.stateID

See 2.2.2. References a given MolecularState of a given MolecularChemicalSpecies. 50 Chapter 7. States.Molecules

7.6.2 MolecularStateType.Description String giving a name to the state.

7.6.3 MolecularStateType.MolecularStateCharacterisation Type: MolecularStateCharacterisationType. It describes all quantities related to the molecular state apart from quantum numbers (e.g. statistical weights, Land´efactors, radiative lifetime of the level and other properties).

7.6.4 MolecularStateType.TotalSpinMomentumS Provides the total electronic spin of the MolecularChemicalSpecies (see Appendix B). It is of type MolecularQuantumNumberType.

7.6.5 MolecularStateType.Parity MolecularStateType.Parity gives the total parity of the level (see Appendix B). It is of type ParityType (a token taking the values odd or even).

7.6.6 MolecularStateType.TotalMagneticQuantumNumberS Provides the projection of total electronic spin on a specific axis (see Appendix B). It is of type MagneticQuantumNumberType.

7.6.7 MolecularStateType.ElectronicHome Associated to the object ElectronicHomeType. See below

7.7 MolecularStateCharacterisationType 7.7. MolecularStateCharacterisationType 51

7.7.1 MolecularStateCharacterisationType.StateEnergy Eigenvalue of the hamiltonian describing the chemical species. It is an extension of type DataType with an attribute energyOrigin. energyOrigin is a human readable string indi- cating the nature of the origin taken for the energy scale. For example, energyOrigin might be ground electronic, vibrational, rotational state or could be ionization energy or dissociation energy.

7.7.2 MolecularStateCharacterisationType.TotalStatisticalWeight Statistical weight associated to the level including all degeneracies (including nuclear spins). It is a positive integer.

7.7.3 MolecularStateCharacterisationType.NuclearStatisticalWeight The same as TotalStatisticalWeight for nuclear spin states only. It is a positive integer.

7.7.4 MolecularStateCharacterisationType.NuclearSpinSymmetryType A string indicating the type of nuclear spin symmetry. Possible values can be para, ortho, meta, A, E. This element is a comfort element very often used to classify levels.

7.7.5 MolecularStateCharacterisationType.Lifetime It is of type DataType. Intrinsic lifetime of a level due to its total radiative decay. When only discrete radiative decay is involved, it is given by 1 τi = (7.1) Pk Aik 52 Chapter 7. States.Molecules

(see object DataType)

7.7.6 MolecularStateCharacterisationType.Parameters It is unbounded and of type CharacterisationType. It allows to add additional characteri- sation of the molecular state. As an example it can be used to describe a statistical weight associated to the level including some degeneracies, but not all. In that case the element ”Parameter.Name” takes the value PseudoStatisticalWeight. This PseudoStatisticalWeight must be absolutely docu- mented. It does not include all degeneracies and is used in fractions. As an example, CDMS database provides such PseudoStatisticalWeight. As another example it can be used to describe a nuclear statistical weight associated to the level including some degeneracies, but not all. In that case the element ”Parameter.Name” takes the value PseudoNuclearStatisticalWeight. This PseudoNuclearStatisticalWeight must be absolutely documented. It does not include all degeneracies and is used in fractions. As an example, such NuclearPseudoStatisticalWeight can be extracted from CDMS database. 7.8. ElectronicHomeType 53

7.8 ElectronicHomeType

The ElectronicHomeType describes quantities related to the electronic state of the MolecularChemicalSpecies The state is given as a linear combinaison of ElectronicComponent of type ElectronicComponentType (see below). The wavefunctions of levels are often expressed as eigenvectors that are linear combinations (given by basisComposition) of basis states in one of the standard coupling schemes. The component corresponds to one component entering the expansion of the eigenstate caracter- izing the level.

7.9 ElectronicComponentType

The ElectronicComponentType describes one component of the electronic eigenstate.

7.9.1 ElectronicComponentType.Description A human readable string describing the electronic state.

7.9.2 ElectronicComponentType.SerialQuantumNumber A serial number that labels states to which no good or nearly good quantum numbers can be assigned to, or a string labelling the states.

7.9.3 ElectronicComponentType.MixingCoefficient It is of type MixingCoefficientType (see below). 54 Chapter 7. States.Molecules

7.9.4 ElectronicComponentType.ElectronicCharacterisation It provides all characterisation of the electronic state apart from quantum numbers. It is of type ElectronicCharacterisationType (see below).

7.9.5 ElectronicComponentType.TotalMolecularProjectionL It gives the projection onto the molecular fixed axis of the electronic total orbital angular mo- mentum of the MolecularState (see Appendix B). It is of type MolecularQuantumNumberType.

7.9.6 ElectronicComponentType.VibrationalHome Associated to the object VibrationalHomeType. See below

7.10 ElectronicCharacterisationType

7.10.1 ElectronicComponentType.TermSymbol It gives the spectroscopic notation describing the term to which this quantum state belongs, if applicable. It is of type SymbolType. For molecular quantum states, it is a shorthand expression of the group irreductible rep- resentation and angular momenta that characterize the state of a molecule, i.e. its elec- tronic quantum state. A complete description of the molecularTermSymbol can be found in Notations and Conventions in Molecular Spectroscopy: Part 2. Symmetry notation Schutte et al. (1997b). The molecular term symbol contains the irreductible representation for the molecular point groups with right subscripts and superscripts, and a left superscript indicating the electron spin multiciplicity, additionally it starts with a symbol X˜ (ground state), A˜, B˜, ... indicating excited states of the same multiplicity than the ground state X or a˜, B˜, ... for excited states of different multiplicity. (Note : For diatomic molecules there is no ˜ on the letters).

7.10.2 ElectronicComponentType.Configuration a string describing the configuration of the molecular electronic state. It is of type ReferencedTextType.

7.10.3 ElectronicComponentType.Conformation It is a string giving the conformation, such as cis, trans, etc. 7.11. VibrationalHomeType 55

7.10.4 ElectronicComponentType.SymmetryGroup

It concerns the symmetry groups of the molecule in that particular electronic state. It is of type SymbolType. It can be the Molecular Point Group, the Molecular Symmetry Group, the permution- inversion group, etc. Descriptions can be found in Notations and Conventions in Molecular Spectroscopy: Part 2. Symmetry notation, Schutte et al. (1997b) and in the book of Bunker.

7.11 VibrationalHomeType

The VibrationalHomeType describes quantities related to the vibrational state of the MolecularState.

7.11.1 ElectronicHomeType.Polyad

The state can belong to a given Polyad of type CharacterisationType (see below). The element Name is a string giving the type of polyad, such as ground state, dyad, pentad, octad, etc. and the StringValue represents the polyad, such as P0, P1, P2, etc.

7.11.2 ElectronicHomeType.VibrationalComponent

The state is given as linear combinaison of VibrationalComponent of type VibrationalComponentType (see below).

7.12 VibrationalComponentType

The VibrationalComponentType describes one component of the vibrational eigenstate. 56 Chapter 7. States.Molecules

7.12.1 VibrationalComponentType.Description

A human readable string describing the vibrational state (example: nu1, nu2, ..).

7.12.2 VibrationalComponentType.SerialQuantumNumber

A serial number that labels states to which no good or nearly good quantum numbers can be assigned to, or a string labelling the states.

7.12.3 VibrationalComponentType.MixingCoefficient

It is of type MixingCoefficientType (see below).

7.12.4 VibrationalComponentType.VibrationalCharacterisation

It characterizes the vibrational state in addition or in place of VibrationalQuantumNumbers. It is of type VibrationalCharacterisationType. See below.

7.12.5 VibrationalComponentType.VibrationalQuantumNumbers

It describes the VibrationalQuantumNumbers. Itisoftype VibrationalQuantumNumbersType. see below

7.12.6 VibrationalComponentType.RotationalHome

Associated to the object RotationalHomeType. See below 7.13. VibrationalCharacterisationType 57

7.13 VibrationalCharacterisationType

7.13.1 VibrationalCharacterisationType.VibrationalSpeciesNotation It is the symmetry species symbol for pure vibrational levels when relevant (see Appendix B). It is of type SymbolType.

7.13.2 VibronicCharacterisationType.VibronicSpeciesNotation It is the symmetry species symbol for vibronic levels when relevant. It is of type SymbolType.

7.14 VibrationalQuantumNumbersType

This type describes the vibrational quantum numbers for the MolecularState.

7.14.1 VibrationalQuantumNumbersType.VibrationalNu

It describes the vibrational mode vi (following Mulliken conventions). By defaut the vibrational mode is a normal mode. It is of type ComplexMolecularQuantumType(see below).

7.14.2 VibrationalQNType.TotalVibrationL total vibrational angular momentum. It is the sum of all angular momenta ±li associated to degenerate vibrations: lν = | Pi(±li)|. It is of type MolecularQuantumNumberType.

7.14.3 VibrationalQuantumNumbersType.VibronicAngularMomentumK is the sum of the total vibrational angular momentum lν and of the electronic orbital momentum about the internuclear axis Λ: K = | ± lν ± Λ|; here K, lν, Λ are unsigned quantities. This is used for linear polyatomic molecules. (see p. 25 Volume III of Herzberg, and REC. (recommendation) 17 of Mulliken (1955)). 58 Chapter 7. States.Molecules

7.14.4 VibrationalQuantumNumbersType.VibronicAngularMomentumP

is the sum of the total vibrational angular momentum lν and of the total electronic orbital momentum about the internuclear axis Ω: P = | ± lν ± Ω|; here P , lν, Ω are unsigned quantities. This is used for linear polyatomic molecules. (see p. 26 Volume III of Herzberg, and REC. 18 of Mulliken (1955))

7.15 RotationalHomeType

The RotationalHomeType describes quantities related to the rotational state of the MolecularChemicalSpecies.

7.15.1 RotationalHomeType.RotationalCharacterisation

It characterizes the rotational state in addition or in place of RotationalComponent. It is of type ‘RotationalCharacterisationType” (See below).

7.15.2 RotationalHomeType.RotationalComponent

The state is given as linear combinaison of RotationalComponent of type RotationalComponentType (see below). 7.16. RotationalCharacterisationType 59

7.16 RotationalCharacterisationType

7.16.1 RotationalCharacterisationType.RoVibrationalSpeciesNotation symmetry species symbol for rovibrational levels when relevant. It is of type SymbolType.

7.16.2 RotationalCharacterisationType.RoVibronicSpeciesNotation symmetry species symbol for rovibronic levels when relevant. It is of type SymbolType.

7.16.3 RotationalCharacterisationType.RoVibronicAngularMomentumP total resultant axial angular momentum quantum number including electron spin: P = |K+Σ|. (REC. 26 Mulliken (1955))

7.16.4 RotationalCharacterisationType.PermutationSymmetry

Its value is a or s. It classifies rovibrational or rovibronic levels of symmetric linear molecules with respect to the exchange of sets of identical nuclei ( Mulliken (1955)). It is of type PermutationSymmetryType

7.16.5 RotationalCharacterisationType.InversionSymmetry

It describes the symmetry of the ro-vibrational wavefunction describing the umbrella motion. It is of type PermutationSymmetryType. 60 Chapter 7. States.Molecules

7.17 RotationalComponentType

The RotationalComponentType describes one component of the rotational eigenstate. It is composed of 2 elements describing the molecules of C∞v symmetry, given by the element diatomAndLinearPolyatomic of type DiatomAndLinearPolyatomicType or the other sym- metries, given by the element nonLinearPolyatomic of type NonLinearPolyatomicType (see below). A MixingCoefficient of type MixingCoefficientType is attached to this component.

7.17.1 RotationalComponentType.MixingCoefficient

It is of type MixingCoefficientType (see below).

7.17.2 RotationalComponentType.SerialQuantumNumber

A serial number that labels states to which no good or nearly good quantum numbers can be assigned to, or a string labelling the states.

7.18 DiatomAndLinearPolyatomicType

This type is separated in 3 cases corresponding to 1Σ states with no hyperfine cou- pling given by the element LinearNoElecNoHyperF of type LinearNoElecNoHyperFType, to 1Σ states with hyperfine coupling given by the element LinearNoElecHyperF of type LinearNoElecHyperFType, to open shell systems given by the element LinearElecCoupling of type LinearElecCouplingType. 7.19. LinearNoElecNoHyperFType 61

7.19 LinearNoElecNoHyperFType

7.19.1 LinearNoElecNoHyperFType.TotalAngularMomentumN Gives the rotational angular momentum N as described in Appendix B. It is of type MolecularQuantumNumberType

7.19.2 LinearNoElecNoHyperFType.TotalMagneticQuantumNumberN Gives the projection of N of space-fixed axis. It is described in Appendix B. It is of type MagneticQuantumNumberAngularType.

7.20 LinearNoElecHyperFType

7.20.1 LinearNoElecHyperFType.TotalAngularMomentumN Gives the rotational angular momentum N as described in Appendix B. It is of type MolecularQuantumNumberType

7.20.2 LinearNoElecHyperFType.HyperfineQuantumNumbers Gives all quantum numbers related to hyperfine couplings. It is of type HyperfineQuantumNumbersType (see definition).

7.21 HyperfineQuantumNumbersType

The HyperfineQuantumNumbersType is a type used in different coupling cases. It includes a group HyperfineCouplingISum which includes all possible intermediate quantum numbers resulting from couplings among spins or between a spin and another angular momentum.

It includes as well the total angular momentum F and its magnetic component. 62 Chapter 7. States.Molecules

7.21.1 HyperfineQuantumNumbersType.TotalAngularMomentumF

Gives the total angular momentum F including nuclear spins, as described in Appendix B. It is of type ComplexMolecularQuantumNumberType.

7.21.2 HyperfineQuantumNumbersType.TotalMagneticQuantumNumberF

Gives the projection of N of space-fixed axis. It is described in Appendix B. It is of type MagneticQuantumNumberAngularType.

7.22 HyperfineCouplingISum

It is a group which has an unbounded sequence of elements ISum and IntermediateHyperfineQuantumNumber which are both of type ComplexMolecularQuantumNumber. In ComplexMolecularQuantumNumber the attribute group nuclearSpinCharacteristics will be used (see below).

7.22.1 HyperfineCouplingISum.ISum

ISum is of type ComplexMolecularQuantumNumber and will provide the sum of 2 spins. In order to identify the origin of the spins, any attribute refering to 2 spins can be used (see below)

7.22.2 HyperfineCouplingISum.IntermediateHyperfineQuantumNumber

IntermediateHyperfineQuantumNumber is of type ComplexMolecularQuantumNumber and will provide the sum of a spin (identified by any attribute related to spins) and of a quantum number other than spin (identified by quantumNumberRef).

7.23 LinearElecCouplingType

For open-shell molecules, the LinearElecCouplingType contains all relevant symmetries, coupling cases and related quantum numbers. It is composed of a Description element, the EfSymmetry element and the different coupling cases. Cases with and without hyperfine couplings are again considered. The different coupling cases without hyperfine couplings are described in HundCaseA of type HundCaseAType , in HundCaseB of type HundCaseBType. The different coupling cases with hyperfine couplings are described in HyperfineCaseAAlpha of type HyperfineCaseAAlphaType, in HyperfineCaseABeta of type HyperfineCaseABetaType, in HyperfineCouplingHundCaseB of type HyperfineCouplingBType. All the electronic coupling Hund’s cases and hyperfine coupling cases are indicated in Appendix C. The definition of quantum numbers are given in Appendix B. 7.24. HundCaseAType 63

7.23.1 LinearElecCouplingType.Description

A string labeling the state.

7.23.2 LinearElecCouplingType.EfSymmetry

It is of type EfSymmetryType, i.e. a string indicating the e/f symmetry. The only values are e or f.

7.24 HundCaseAType 64 Chapter 7. States.Molecules

7.25 HundCaseBType

7.26 HyperfineCaseAAlpha

7.27 HyperfineCaseABeta

7.28 HyperfineCouplingHundCaseB 7.29. NonLinearPolyatomicType 65

7.29 NonLinearPolyatomicType

This section describes symmetries and quantum numbers for non linear polyatomic molecules. We distinguish the case of close-shell cases given by the element NonLinearNoElecNoHyperF (without hyperfine coupling) and NonLinearNoElecHyperF (with hyperfine coupling) from the open-shell cases given by the element NonLinearElecNoHyperF (without hyperfine coupling) and NonLinearElecHyperF (with hyperfine coupling)

7.30 NonLinearNoElecNoHyperFType

It is an extension of NonLinearNoElecType (see below) with an additional element TotalMagneticQuantumNumberN

7.30.1 NonLinearNoElecNoHyperF.TotalMagneticQuantumNumberN

Gives the projection of N of space-fixed axis. It is described in Appendix B. It is of type MagneticQuantumNumberType. 66 Chapter 7. States.Molecules

7.31 NonLinearNoElecType

7.31.1 NonLinearNoElec.TotalAngularMomentumN

Gives the rotational angular momentum N as described in Appendix B. It is of type AngularMomentumType.

7.31.2 NonLinearNoElec.MolecularProjection

It is of type MolecularProjectionType (see below) which contains all the molecular fixed projections for symmetric and asymmetric tops.

7.31.3 NonLinearNoElec.C2Symmetries

It is of type C2SymmetriesType (see below) which contains all the C2 symmetries.

7.32 NonLinearNoElecHyperFType

It is an extension of NonLinearNoElecType (see above) with an additional element HyperfineQuantumNumbers of type HyperfineQuantumNumbersType (see below).

7.33 NonLinearElecNoHyperFType

It is an extension of NonLinearElecCouplingType with an additional element TotalMagneticQuantumNumberJ of type MagneticQuantumNumberType (see below). 7.34. NonLinearElecHyperFType 67

7.34 NonLinearElecHyperFType

It is an extension of NonLinearElecCouplingType with an additional element HyperfineQuantumNumbers of type HyperfineQuantumNumbersType (see definition). 68 Chapter 7. States.Molecules

7.35 NonLinearElecCouplingType

It includes the element Label, a string giving a description of the state EfSymmetry of type EfSymmetryType (already defined) TotalAngularMomentumN, TotalAngularMomentumJ (Gives the rotational angular momenta N and J as described in Appendix B MolecularProjection of type MolecularProjectionType (already defined) RoVibronicSplitting of type RoVibronicSplittingType (see below)

7.36 RoVibronicSplittingType

It is an extension of PrimaryType with elements Label and Type. It identifies the splitting’s components due to rovibronic interactions. The levels are labeled (+l), (−l), (+j), (−j) (Vol. III, Herzberg). The element RoVibronicSplitting.Type is a string describing the nature of the interaction giving rise to the splitting. The element RoVibronicSplitting.Label is a string containing either (+l), (−l), (+j) or (−j). 7.37. MolecularProjectionType 69

7.37 MolecularProjectionType

It gives the molecular projections for symmetric and asymmetric molecules.

7.37.1 MolecularProjectionType.TotalMolecularProjectionN

It is the absolute value of the molecular fixed projection of N. See appendix B.

7.37.2 MolecularProjectionType.AsymmetricProjection

It provides the molecular fixed projections for asymmetric top molecules with the elements AsymmetricTau (τ), AsymmetricKa (ka), AsymmetricKc (kc) [See Appendix B]. It is of type AsymmetricProjectionType

7.37.3 MolecularProjectionType.HinderedMotion

It provides 2 additional projection quantum numbers : HinderedK1 and HinderedK2, such 2 that the total rotational energy is given by: F (N,K,k1,k2) = BN(N + 1) − BK + 2 2 A1k1 + A2k2 where N is TotalAngularMomentumN, K is TotalMolecularProjectionN, k1 is HinderedK1 and k2 is HinderedK2 (see p. 492, Volume II of Herzberg). It is of type HinderedMotionType. 70 Chapter 7. States.Molecules

7.38 C2SymmetriesType

It indicates the symmetries c2aSymmetry, c2bSymmetry, c2cSymmetry for symmetric and asymmetric molecules.

7.39 CharacterisationType

The CharacterisationType is derived from a PrimaryType and is composed of a Name and of a value that can be an integer, a float or a string.

7.40 MixingCoefficientType

A positive or negative number (double) giving the squared or the signed linear coefficient corresponding to the associated electronicComponent in the expansion of the electronic eigenstate. It varies from 0 to 1 (or -1 to 1). This type is an extension of a xs:double with an attribute mixingClass of type MixingClassType. MixingClassType is a string (token) that can take 2 values only: squared or “signed’. 7.41. SymbolType 71

7.41 SymbolType

It is a model to describe symbols. It is derived from a PrimaryType with unbounded elements Symbol of type SimpleSymbolType and an element LatexExpression allowing the user to enter the symbol as a simple latex expression.

The SimpleSymbolType is composed of a Central Symbol of type CentralSymbolType and of a RightCoefficient and LeftCoefficient. 72 Chapter 7. States.Molecules

7.42 MolecularQuantumNumberType

It has an attribute quantumNumberID of type xs:ID which is composed of the upper-case letter Q followed by one or more symbols. It has 3 elements: Label which is a string labelling the quantum number, Value which is of type AngularMomentumType, Description that might be used to specify quantum numbers not explicitly given in this document.

7.43 ComplexMolecularQuantumNumberType

This is an extension of MolecularQuantumNumberType (quantumNumberID, a Label, a Value) with 2 groups of attributes: vibrationModeCharacteristics and nuclearSpinCharacteristics. 7.43. ComplexMolecularQuantumNumberType 73 74 Chapter 7. States.Molecules

7.43.1 ComplexMolecularQuantumNumberType.modesType The attribute modesType gives the type of vibration mode: normalMode bendingMode streching mode torsionalMode inversionMode localMode If the vibrational mode is fairly localised, the bond description will be indicated in the ele- mentLabel of MolecularQuantumNumberType.

7.43.2 vibrationLNu-i angular momentum associated to degenerate normal vibrations, li = vi,vi−2,vi−4,..., 1 or 0. It is of type AngularMomentumType.

7.43.3 ComplexMolecularQuantumNumberType.vibrationSymmetry

A string describing the species symbol for individual vibrational modes vi (type vibrationNu i). It can be σ, π, a, b, etc. usually with subscript or superscripts.

7.43.4 ComplexMolecularQuantumNumberType.vibrationInversion Its value is + or -. It classifies the inversion doubling component for a given vibrational modes + − vi. Note: The total notation for an inversion doubling component is vi or vi . It is only used for type vibrationNu i.

7.43.5 ComplexMolecularQuantumNumberType.vibrationSymmetryIndex It is an index labelling the vibration symmetry as the same vibration symmetry might be found several times.

We describe here the group attribute nuclearSpinCharacteristics which is attached to the ComplexMolecularQuantumNumberType. This group attribute is composed of pointers (or references) to quantum numbers IDs. Among all pointers, only 2 references can be given since these pointers identify the quantum numbers originating Isum or IntermediateHyperfineQuantumNmber.

7.43.6 ComplexMolecularQuantumNumberType.nuclearSpinRefs2 It is of type xs:IDREFS and contains 2 references only. These references point to 2 nuclear spins (identified in AtomNType by nuclearSpinID) whose sum will be given in ISum.

7.43.7 ComplexMolecularQuantumNumberType.nuclearSpinRef It is of type xs:IDREF and points to 1 nuclear spin (identified in AtomNType by nuclearSpinID)

7.43.8 ComplexMolecularQuantumNumberType.spinSumRef It is of type xs:IDREF and points to the sum of 2 spins (identified in “Isum’. 7.43. ComplexMolecularQuantumNumberType 75

7.43.9 ComplexMolecularQuantumNumberType.electronicSpinRef It is of type xs:IDREF and points to the electronic spin (identified in TotalSpinMomentumS).

7.43.10 ComplexMolecularQuantumNumberType.quantumNumberRef It is of type xs:IDREF and points to a quantum number other than spin or sum of spins. 76 Chapter 7. States.Molecules 77

Chapter 8

Processes and Processes.Radiative

8.1 ProcessesType

One of the primary elements of XSAMS is Processes of type ProcessesType. This type de- scribes radiative, non-radiative (e.g., autoionization), and collisional processes between atoms, molecules, solids, and elementary particles.

8.2 Processes.Radiative

This part of the schema describes radiative processes including spontaneous radiative de- cays. Collisions between photons and various objects (e.g., molecules) are described in the Processes.Collisions part.

8.3 RadiativeType

Extension of the PrimaryType; contains one or more radiative transitions. 78 Chapter 8. Processes and Processes.Radiative

8.4 RadiativeTransitionType

Extension of the PrimaryType. A transition is characterized by its energy/wavelength (el- ement EnergyWavelength of type EnergyWavelengthType) and optional parameters such as InitialStateRef (reference to the stateID of the initial state of the transition, type StateRef), FinalStateRef (reference to the stateID of the final state of the transition, type StateRef), and unbounded list of elements Probability of type RadiativeTransitionProbabilityType. Different values of probabilities may be due to different multipole orders (e.g., M1 and E2 may be possible for the same initial and final states).

8.5 EnergyWavelengthType

Extension of the PrimaryType. May contain Wavenumber, Wavelength, Energy, or Frequency. All these elements are of type WavelengthWavenumberType. 8.6. WavelengthWavenumberType 79

8.6 WavelengthWavenumberType

Extension of the PrimaryType. Used for description of wavelengths, wavenumbers, frequencies and energies. Element Ritzis the value of, e.g., a wavelength derived from the experimen- tal energy levels, element Theoretical (type DataType) is a calculated value, and element Experimental if the measured/observed value. All three are of type DataType. 80 Chapter 8. Processes and Processes.Radiative

8.7 RadiativeTransitionProbabilityType

Extension of the PrimaryType. Describes the following optional elements (all of type DataType): TransitionProbabilityA, OscillatorStrength, LineStrength, WeightedOscillatorStrength, Log10WeightedOscillatorStrength, IdealisedIntensity. Also may contain element Multipole of type MultipoleType.

8.7.1 TransitionProbabilityA

Einstein coefficient, or transition probability.

8.7.2 OscillatorStrength

Oscillator strength (dimensionless). Whether it is absorption or emission, is determined from the initial and final states of the transition. 8.7. RadiativeTransitionProbabilityType 81

8.7.3 LineStrength A symmetric quantity with respect to initial and final states of the transition.

8.7.4 WeightedOscillatorStrength Product of the oscillator strength and statistical weight of the initial state.

8.7.5 Log10WeightedOscillatorStrength

Log10 of the WeightedOscillatorStrength.

8.7.6 IdealisedIntensity Line intensity under specific conditions. Due to its dependence on plasma parameters, this is not a universal property of a spectral line and thus should be used with care.

8.7.7 Multipole Multipole order of a radiative transition (electric or magnetic). It is a string with the first upper-case symbol E or M followed by one or more digits, and the first digit cannot be 0. 82 Chapter 8. Processes and Processes.Radiative 83

Chapter 9

Processes.NonRadiative

Describes typical processes of a spontanous decay without photons, for instance, autoionization or predissociation.

9.1 NonRadiativeType

Extension of the PrimaryType. Must have one or more non-radiative transitions.

9.2 NonRadiativeTransitionType

Extension of the PrimaryType. The InitialStateRef is mandatory while the FinalStateRef is optional; both elements are of type StateRef. Probability (type DataType) is manda- tory as well because making it optional would remove all meaningful physics from this section. TransitionEnergy (type DataType) is the energy difference between the initial and final states. The optional parameter Type (xs:string) may provide additional details (e.g., indi- cate that this is a Coster-Kronig process). 84 Chapter 9. Processes.NonRadiative 85

Chapter 10

Processes.Collisions

The element Collisions of the object Processes is of type CollisionsType and contains one or more elements CollisionalTransition. The complex element CollisionalTransition provides:

• the physical information to fully describe any collision involving photons, atoms, ions, molecules and elementary particles such as electrons or photons, and any particle solid interaction (PSI)

• the numerical data, either in a tabulated form or described by a fit function, or both

10.1 CollisionalTransition

Element CollisionalTransition of type CollisionalTransitionType, extension of PrimaryType includes 6 primary elements:

• reaction process

• reactants

• intermediate states if known

• products if known

• threshold if applicable

• numerical datasets 86 Chapter 10. Processes.Collisions

10.1.1 ProcessClass

The element ProcessClass of type ProcessClassType describes the collision process or particle surface interaction. It is a combination of three optional elements:

• user defined

• a list of XSAMS codes

• an IAEA code 10.1. CollisionalTransition 87

The UserDefinition element is a free label for the xml file producer to define the process. One or more elements Code are allowed as well. Values are a combination of simple four-letter codes (see Annex ?). Taking examples for common processes, excitation has one value exci; and dissociative recombination has two values diss and reco. Element IAEACode is a list of processes established by the DATA Centre Network (DCN) of the IAEA. Its initial purpose was the development of search engines for atomic and molecular data. Processes, represented with a three-letter code, are classified in four categories: electron collisions, photon collisions, heavy particle collisions and particle surface interactions (see Annex E).

10.1.2 ReactantsType and ProductsType Reactants, intermediate states and products are defined by references StateRef (type xs:IDREF pointing to stateID defined in 2.2.2). Refer to States chapter for a full description of all possible states. Element Reactants is of type ReactantsType while elements Products and IntermediateState are of type ProductsType. Both are unbounded sequences of StateRef. The difference be- tween the two types resides within their sequence bounds: 2 to infinity for ReactantsType (there must be at least two reactants for a collisional process) and 1 to infinity for ProductsType.

10.1.3 Threshold The reaction threshold is the minimum energy required to initiate a reaction, often needed in using data such as rate coefficients. Threshold is of type DataType (see Chapter Attributes 88 Chapter 10. Processes.Collisions and Types).

10.2 DataSets and DataSet

Element Datasets provides numerical data for a specific reaction. It is an unbounded sequence of elements DataSet, therefore different datasets may be provided for the same reaction. Datasets differ at this level by their data quantities (dataDescription attribute) such as rate coefficients or cross sections for collisions, reflection coefficients or mean penetration depth for PSI data, etc.

Element DataSet, of type DataSetType, provides numerical data as tabulated data (TabulatedData element) or as the parameters values and validity limits of a fit function (FitData element). The fit function is defined in the element Functions.

The DataSetType type is an extension of the primary type PrimaryType. Its attribute dataDescription specifies the type of data (rate coefficients or sputtering yields for ex- ample). DataSetType has two optional unbounded elements: FitData and TabulatedData. Data are therefore fit data or tabulated data or both. At this level, they may be issued from different sources or methods (unbounded element) but must refer to the same data quantity, as the dataDescription attribute is an attribute of the DataSet element. 10.2. DataSets and DataSet 89

10.2.1 FitData

The FitData element of type FitDataType (extension of PrimaryType) gives all data nec- essary to calculate the numerical output using a fit function. The child element FunctionRef refers to this fit function which is defined in the Functions element. Data are of two types:

• the validity limits of the arguments (x1, x2...)

• the fit parameter values

To complete the description, the fit accuracy, the physical uncertainty and the data production date may be reported.

FunctionRef

The FunctionRef element of type xs:IDREF is a reference to a fit function defined in the Functions element. Its regular expression is F.+. 90 Chapter 10. Processes.Collisions

FitValidityLimits

This mandatory element of type FitValidityLimitsType is unbounded as arguments may be multiple. For example, differential cross sections can have dependance on angle and en- ergy. It provides the fit validity limits, available lower and upper values, for each argument of the fit function. The FitValidityLimits element has two optional child elements of type xs:double: LowerLimit and UpperLimit.

To ensure data consistency, the number of occurences of the element FitValidityLimits must reflect the number of arguments defined for the fit functions, and validity limits must be listed in the same sequence as the arguments defined within the fit function (see Chapter ”Functions”).

FitParameters and Parameter

The FitParameters element of type FitParametersType is a sequence of unbounded ele- ments Parameter of predefined type xs:double.

Each Parameter element gives the value of its corresponding fit parameter defined in the fit function referenced within the element FunctionRef. For data consistency, it is essential to ensure an exact matching of the parameter values with their definition.

FitAccuracy and PhysicalUncertainty

These two elements are of the predefined type xs:string. No rules have been set for their description as yet.

ProductionDate

This element, of type xs:date, is the data production date.

10.2.2 TabulatedData This element of type TabulatedDataType, extension of the primary type PrimaryType, pro- vides the necessary information to describe the numerical data in a tabulated form. It includes 10.2. DataSets and DataSet 91 the elements DataXY, ReferenceFrame, PhysicalUncertainty and ProductionDate (see subsection FitData for definitions).

DataXY

The DataXY element of type DataXYType provides the numerical data in a tabulated form. It has two elements X and Y of same type DataTableType. The element X is unbounded to allow description of data depending on more than one variable, as for example: y = f(x1, x2, x3).

DataTableType

The DataTableType is the type used for the two elements X and Y. 92 Chapter 10. Processes.Collisions

It has two attributes: • a mandatory one units of type UnitType (see section “Types and Attributes”) • an optional one parameter to describe the type of unit (e.g., energy, time, or surface...) The DataList element provides the numerical values as a list. Each value may have optional errors bars, listed within the following elements: • element Error: centered error bar • element PositiveError • element NegativeError All these elements have the same type DataListType (list of values of type xs:double). All missing error values should be reported as -1. Each numerical list from any X or Y element must have the same number of values. This is necessary to transfer in a consistant way the numerical data. This way, the nth value of the DataList element of the Y element has as argument values the nth value of the DataList element from each X element. It is important to note that no missing values are possible within the DataList element, as each Y value has always a defined set of X values. 10.2. DataSets and DataSet 93

The following table:

Table 10.1: Differential cross sections in 10−16cm2

x1 (eV) | x2 (deg) | 0 20 40 1. | .1 .2 .3 2. | .4 .5 .6 3. | .7 .9

produces as output:

ReferenceFrame For numerical data depending on such parameters as energy or velocity, it is important to know in which frame this dependence is calculated. The element Reference is of type string. Possible values are Center of Mass or Projectile Energy for example.

PhysicalUncertainty and ProductionDate see subsection FitData 94 Chapter 10. Processes.Collisions 95

Chapter 11

Methods

The element Methods provides the list of different methods used to produce numerical data. It is of type MethodsType and contains one or more elements Method.

11.1 Method

Element Method provides information on a specific method used to produce numerical data reported in the xml file. Examples of numerical data include energy levels for atoms and molecules, wavelengths for radiative transitions, cross sections for atomic and molecular colli- sions, etc. Element Method is identified by an ID which is then referred to in the data section. Method is of type MethodType and has three attributes and three elements:

• mandatory attribute methodID of type xs:ID, which is the method identification to which any numerical data can refer. This attribute must be composed of a capital letter M followed by one or more symbols.

• optional attribute sourceRef of type xs:IDREF, which is the reference to the source of the description of the method, if this source is different from the numerical data source.

• optional attribute functionRef of type xs:IDREF, which is a reference to a fit function that was used within this particular method. This attribute is optional and has for regular expression: F.+.

• mandatory element Category, of type CategoryType is an item from the following list of methods:

– experiment

– theory

– recommended

– evaluated

– empirical

– scalingLaw 96 Chapter 11. Methods

– semiempirical

– compilation

– derived

– observed

• mandatory element Description, of type xs:string, which is a free format text to describe the method.

• optional element Comments, of type xs:string, is a free format string to give any further information. 97

Chapter 12

Functions

Element Functions provides the list and description of different functions used for data pre- sentation. These functions can be fit functions to calculate numerical data or functions to describe specific methods. The Functions element is of type FunctionsType and contains one or more elements Function.

12.1 Function

Element Function of type FunctionType provides description of a function in terms of its value y, arguments x1, x2..., and additional parameters. Each function is identified by an ID to which the fit data (FitData element) or the method (Method element) refers. FunctionType is an extension of PrimaryType.

It is important to note that a fit function can be viewed just as a mathematical expression or as the representation of physical process. This second approach has been priviledged in XSAMS. Therefore, physical parameters, such as units or the reference frame for the energies are described in this section. Numerical data for the argument validity limits and the fit pa- rameters are provided as fit data within the Transitions.Collisions Chapter (see FitData subsection). 98 Chapter 12. Functions

The attribute functionID of type xs:ID is the function identification to which any numerical data or method can refer. This attribute is mandatory and has a regular expression: F.+

Child elements of the Function element are:

• Name, of type xs:string, which gives the name of the function

• Parameters is a unbounded list to describe the parameters of the function. It is of type ParametersType. 12.2. Expression 99

• Description, of type xs:string, gives a description of the function

• SourceCodeURL, of type xs:string, is a location from where the source code can be downloaded.

12.2 Expression

Element Expression, of type ExpressionType, is the function expression in a specified pro- gramming language. The language is specified within the attribute computerLanguage.

A fit function with the expression a*x1 + b*x1**2 + c has:

• the value fortran or C or ... for the computerLanguage attribute of the element Expression

• one argument x1 in its argument list

• three parameters a, b and c in its parameter list

12.3 Y

The element Y, of type ArgumentType, describes the value of the fit function, providing its units and type.

12.4 Arguments

The element Arguments, of type ArgumentsType, provides the unbounded list of the function arguments as a sequence of elements Argument of type ArgumentType.

12.5 ArgumentType

ArgumentType applies here to the Y and Argument elements (see above). It has two attributes, mandatory units and optional parameter, and two elements, mandatory Name and optional Description. 100 Chapter 12. Functions

The units attribute, of type xs:token, is an enumeration of given units (see Types and Attributes Chapter). The parameter attribute provides the type of units, e.g. energy, frequency, etc. The element name is the name of the corresponding function argument or fit function output used in the fit function expression (see Expression element). The element description is the description of the argument or the fit function output.

12.6 Parameters

The element Parameters, of type ParametersType provides the list of the function parame- ters as a sequence of unbounded elements Parameter of type ParameterType.

12.7 Parameter

The Parameter element of type ParameterType provides the list of the parameters used in the fit function given within the Expression element. It has 2 elements, one mandatory Name and one optional element Description. 12.8. ReferenceFrame 101

The element Name is the name of the corresponding parameter used in the fit function expres- sion (see Expression element).

The element Description is the description of the parameter.

12.8 ReferenceFrame

See sec. 10.2.2.

12.9 Description

This optional element provides additional information on the the fit function.

12.10 SourceCodeURL

This optional element provides an URL from where the source code of the fit function can be downloaded. 102 Chapter 12. Functions 103

Appendix A

List of Atomic Elements

A.1 Introduction

List of Elements extracted from the IUAPAC Commission on Atomic Weights and Isotopic Abundances. (http://www.chem.qmul.ac.uk/iupac/). The atomic weights (called as well Atomic Mass) have been removed from the original table as they correspond to the average mass of the atoms of an element. This is a weighted average of the naturally-occurring isotopes and this is not relevant for astrophysical applications. The quantities described in this table are:

• the atomic number Z, corresponding to the number of protons found in the nucleus of an atom. The atomic number uniquely identifies a chemical element.

• the symbol

• the name

• the isotopic masses for light atomic species

• nuclear spins for light atomic species

A.2 Isotopic atomic species

Note that isotopic atomic species of a given element is uniquely identified by the mass number A, also called atomic mass number, which is the number of nucleons (protons and neutrons) in an atomic nucleus. The full isotope symbol would also have the atomic number (Z) as a 12 subscript to the left of the element symbol directly below the mass number: 6 C. For the special case of Hydrogen, isotopic atomic species have specific symbols and names:

• 1 neutron and 1 proton: Symbol=“D” and Name=“Deuterium”

• 2 neutrons and 1 proton: Symbol=“T” and Name=“Tritium”

A.3 List of Elements in Atomic Number Order

The names and symbols for elements 112-118 are under review. The temporary system1 recommended by J Chatt, Pure Appl. Chem., 51, 381-384 (1979) is used above. The names of elements 101-109 were agreed in 1997 (see Pure Appl. Chem., 69, 2471-2473, 1997), for element 110 in 2003 (see Pure Appl. Chem., 75, 1613-1615, 2003) and for element 111 in 2004 (see Pure Appl. Chem., 76, 2101-2103, 2004).

1http://www.chem.qmul.ac.uk/iupac/AtWt/element.html 104 Appendix A. List of Atomic Elements

Atomic Number Symbol Name Atomic Mass Number Nuclear Spin

1 H Hydrogen 1 0.5 D Deuterium 2 1 T Tritium 3 0.5 2 He Helium 4 0 3 0.5 3 Li Lithium 7 1.5 6 1 4 Be Beryllium 9 1.5 5 B Boron 11 1.5 10 3 6 C Carbon 12 0 13 0.5 7 N Nitrogen 14 1 15 0.5 8 O Oxygen 16 0 17 2.5 18 0 9 F Fluorine 19 0.5 10 Ne Neon 20 0 21 1.5 22 0 11 Na Sodium 23 1.5 12 Mg Magnesium 24 0 25 2.5 26 0 13 Al Aluminium 27 2.5 14 Si Silicon 28 0 29 0.5 30 0 15 P Phosphorus 31 0.5 16 S Sulfur 32 0 33 1.5 34 0 17 Cl Chlorine 35 1.5 37 1.5 18 Ar Argon 40 0 36 0 38 0 19 K Potassium 39 1.5 40 4 41 1.5 20 Ca Calcium 40 0 42 0 43 3.5 44 0 46 0 48 0 21 Sc Scandium 45 3.5 22 Ti Titanium 46 0 47 2.5 48 0 49 3.5 50 0 23 V Vanadium 51 3.5 50 6 24 Cr Chromium 52 0 50 0 53 1.5 54 0.5 25 Mn Manganese 55 2.5 26 Fe Iron 56 0 54 0 57 0.5 58 0 A.3. List of Elements in Atomic Number Order 105

Atomic Number Symbol Name Atomic Mass Number Nuclear Spin

27 Co Cobalt 59 3.5 28 Ni Nickel 58 0 29 Cu Copper 63 1.5 30 Zn Zinc 64 0 31 Ga Gallium 69 1.5 32 Ge Germanium 74 0 33 As Arsenic 75 1.5 34 Se Selenium 80 0 35 Br Bromine 79 1.5 81 1.5 36 Kr Krypton 84 0 37 Rb Rubidium 85 2.5 87 1.5 38 Sr Strontium 88 0 39 Y Yttrium 89 0.5 40 Zr Zirconium 90 0 41 Nb Niobium 93 4.5 42 Mo Molybdenum 98 0 92 0 94 0 95 2.5 96 0 100 0 43 Tc Technetium 99 2.5 44 Ru Ruthenium 102 0 99 2.5 100 0 101 2.5 104 0 45 Rh Rhodium 103 0.5 46 Pd Palladium 106 0 104 0 105 2.5 108 0 47 Ag Silver 107 0.5 109 0.5 48 Cd Cadmium 114 0 110 0 111 0.5 112 0 113 0.5 116 0 49 In Indium 115 4.5 113 4.5 50 Sn Tin 120 0 51 Sb Antimony 121 2.5 123 3.5 52 Te Tellurium 130 0 53 I Iodine 127 2.5 54 Xe Xenon 132 0 129 0.5 131 1.5 55 Cs Caesium 133 3.5 56 Ba Barium 138 0 57 La Lanthanum 139 3.5 58 Ce Cerium 140 0 59 Pr Praseodymium 141 2.5 60 Nd Neodymium 142 0 143 3.5 144 0 145 3.5 146 0 106 Appendix A. List of Atomic Elements

Atomic Number Symbol Name Atomic Mass Number Nuclear Spin 61 Pm Promethium 62 Sm Samarium 144 0 150 0 152 0 154 0 63 Eu Europium 151 2.5 153 2.5 64 Gd Gadolinium 154 0 155 1.5 156 0 157 0 158 0 160 0 65 Tb Terbium 159 1.5 66 Dy Dysprosium 156 0 158 0 160 0 161 2.5 162 0 163 2.5 164 0 67 Ho Holmium 165 3.5 68 Er Erbium 162 0 164 0 166 0 167 3.5 168 0 170 0 69 Tm Thulium 169 0.5 70 Yb Ytterbium 168 0 170 0 171 0.5 172 0 173 2.5 174 0 176 0 71 Lu Lutetium 175 3.5 72 Hf Hafnium 176 0 177 3.5 178 0 179 4.5 180 0 73 Ta Tantalum 181 3.5 74 W Tungsten 180 0 182 0 184 0 186 0 75 Re Rhenium 185 2.5 76 Os Osmium 187 0.5 188 0 189 1.5 190 0 192 0 77 Ir Iridium 191 1.5 193 1.5 78 Pt Platinum 192 0 194 0 195 0.5 196 0 198 0 79 Au Gold 197 1.5 80 Hg Mercury 196 0 198 0 199 0.5 200 0 201 1.5 202 0 204 0 A.3. List of Elements in Atomic Number Order 107

Atomic Number Symbol Name Atomic Mass Number Nuclear Spin 81 Tl Thallium 203 0.5 205 0.5 82 Pb Lead 206 0 207 0.5 208 0 83 Bi Bismuth 209 4.5 84 Po Polonium 85 At Astatine 86 Rn Radon 87 Fr Francium 88 Ra Radium 89 Ac Actinium 90 Th Thorium 232 0 91 Pa Protactinium 92 U Uranium 235 3.5 238 0 93 Np Neptunium 94 Pu Plutonium 95 Am Americium 96 Cm Curium 97 Bk Berkelium 98 Cf Californium 99 Es Einsteinium 100 Fm Fermium 101 Md Mendelevium 102 No Nobelium 103 Lr Lawrencium 104 Rf Rutherfordium 105 Db Dubnium 106 Sg Seaborgium 107 Bh Bohrium 108 Hs Hassium 109 Mt Meitnerium 110 Ds Darmstadtium 111 Rg Roentgenium 112 Uub Ununbium 113 Uut Ununtrium 114 Uuq Ununquadium 115 Uup Ununpentium 116 Uuh Ununhexium 118 Uuo Ununoctium 108 Appendix A. List of Atomic Elements 109

Appendix B

List of quantum numbers and symmetry identifications

The list contains the quantum numbers in molecular spectroscopy, as well as some symmetry identifications. This list corresponds to the quantum numbers and symmetries found in the description of “Molecules”. The notations for molecular spectroscopy are taken from Schutte et al. (1997a). This document takes into account the paper of Mulliken (1955).

B.1 Note for intermediate coupling

Intermediate coupling occurs in both atomic and molecular physics. Levels can be labelled by the best adapted coupling case, by linear combinaison of pure coupling basis functions (the linear coefficients can be determined in a theoretical approach:this is planned for in the data model, or simply by a sort of serial number (see SerialQuantumNumber below).

B.2 Note for notations of quantum angular momenta for molecules

Angular momemtum basis functions, |AαMA >, can be simultaneous eigenfunctions of three types of operators : the magnitude Aˆ2, the projection of Aˆ onto a molecular symmetry axis Aˆz, and the projection of Aˆ on the laboratory quantization axis AˆZ . The basis function labels 2 2 A, α and MA correspond to eigenvalues of Aˆ , Aˆz and AˆZ , respectively ~ A(A + 1), ~α and ~MA.

B.3 Quantum numbers

B.3.1 nuclearSpin nuclear spin of individual nucleus which composes a molecule. It is given as an attribute of “AtomNType”.

B.3.2 Parity eigenvalue of the parity operator applied to the total wavefunction. It takes the value “even” for even parity and “odd” for odd parity.

B.3.3 SerialQuantumNumber

A serial number or string that labels states to which no good or nearly good quantum numbers can be assigned to. 110 Appendix B. List of quantum numbers and symmetry identifications

B.3.4 AsymmetricTau

Index τ labelling asymmetric rotational energy levels for a given rotational quantum number N. Note: The solution of the Schr¨odinger equation for an asymmetric-top molecule gives for each value of N, (2N + 1) eigenfunctions with its own energy. It is customary to keep track of them by adding the subscript τ to the N value (Nτ ). This index τ goes from −N for the lowest energy of the set to +N for the highest energy, and is equal to Ka − Kc.

B.3.5 AsymmetricKa

For a given N, energy levels may be specified by KaKc (K−1K1, K−K+ are alternative notations), where Ka is the K quantum number for the limiting prolate (B=C) and Kc for the limiting oblate (B=A). In the notation K−1K1, the subscripts 1 and −1 correspond to 2B−A−C values of the asymmetry parameter κ = A−C , where A, B, C are rotational constants of the asymmetric molecule (by definition A > B > C).

B.3.6 AsymmetricKc see AsymmetricKa

B.3.7 AsymmetricTau

Index τ labelling asymmetric rotational energy levels for a given rotational quantum number N. Note: The solution of the Schr¨odinger equation for an asymmetric-top molecule gives for each value of N, (2N + 1) eigenfunctions with its own energy. It is customary to keep track of them by adding the subscript τ to the N value (Nτ ). This index τ goes from −N for the lowest energy of the set to +N for the highest energy, and is equal to Ka − Kc.

B.3.8 TotalSpinMomentumS it is the total electronic spin quantum number S, S can be integral or half-integral. S(S +1)~2 ˆ2 ˆ N is the eigenvalue of the S operator, where S = Pi=1 sˆi.

B.3.9 TotalMagneticQuantumNumberS total electronic spin magnetic quantum number, MS = −S, −S + 1, ..., S − 1,S, where ~MS is the eigenvalue of the SˆZ operator.

B.3.10 TotalMolecularProjectionS total spin projection quantum number Σ, Σ = −S, −S + 1, ..., S − 1,S, where ~Σ is the eigenvalue of the Sˆz operator.

B.3.11 TotalMolecularProjectionL total electronic orbital projection quantum number, Λ = 0, 1,..,L − 1,L, where ~Λ is the absolute value of the eigenvalue of the Lˆz operator (Hund’s cases (a) and (b) in the case of a linear molecule). B.3. Quantum numbers 111

B.3.12 TotalAngularMomentumN is the total angular momentum N exclusive of nuclear and electronic spin, N is integral. For a molecule in a close-shell state “TotalAngularMomentumN” is the pure rotational angular momentum.

B.3.13 TotalMagneticQuantumNumberN total orbital magnetic quantum number, MN = −N, −N + 1,...,N − 1,N, where ~MN is the eigenvalue of the NˆZ operator.

B.3.14 TotalMolecularProjectionN absolute value of the component of the angular momentum N along the axis of a symmetric (or quasi-symmetric) rotor, usually noted K. ±~K is the eigenvalue of the Nˆz operator, with values K = 0,...,N − 1,N. For open shell linear molecules, it corresponds to “TotalMolecularProjectionL” (Λ), so we ad- vise to preferentially use “TotalMolecularProjectionL”.

Note: The symbol K is also used in spectroscopy to describe the component of the vibronic angular momentum (excluding spin) along the axis for linear polyatomic molecules. In this model we prefer to uniquely identify this specific case by a different type of quantum number: “VibronicAngularMomentumK”, defined thereafter.

B.3.15 TotalAngularMomentumJ is the total angular momentum J exclusive of nuclear spin, J can be integral or half-integral. For molecules: ˆ ˆ n ˆ ˆ J = N + Pi=1 sˆi = N + S.

B.3.16 TotalMagneticQuantumNumberJ total magnetic quantum number, MJ = −J, −J + 1,...,J − 1,J, where ~MJ is the eigenvalue of the JˆZ operator.

B.3.17 TotalMolecularProjectionJ absolute value of the component of the angular momentum J along the molecular axis, noted Ω = 0,...,J − 1,J, where ±~Ω is the eigenvalue of the Jˆz operator. For linear molecules with no nuclear spin (or no nuclear spin coupled to the molecular axis), it is the absolute value of the component of the total electronic angular momemtum Lˆ + Sˆ on the molecular axis (Hund’s cases (a) and (c)). When Λ and Σ are defined (Hund’s case (a)): Ω= |Λ ± Σ| (see Appendix C.2) For linear molecules with a nuclear spin coupled to the molecular axis, it includes as well the component ΩI of the nuclear spin on the molecular axis (see Appendix C.2).

B.3.18 TotalAngularMomentumF is the total angular momentum F including nuclear spin, F can be integral or half-integral. F (F + 1)~2 is the eigenvalue of the Fˆ2 operator, where for molecules with m nuclear spins: ˆ ˆ m ˆ ˆ ˆ F = J + Pi=1 Ii = J + I. 112 Appendix B. List of quantum numbers and symmetry identifications

B.3.19 TotalMagneticQuantumNumberF total magnetic quantum number, MF = −F, −F +1,...,F −1, F , where ~MF is the eigenvalue of the FˆZ operator.

B.3.20 VibrationNu vibrational modes vi (following Mulliken conventions). By defaut the vibrational mode is a normal mode. If the vibrational mode is fairly localised, the bond description will be included in the element “Comment” of “ComplexMolecularQuantumNumber”.

B.3.21 VibrationLNu angular momentum associated to degenerate normal vibrations, li = vi,vi−2,vi−4,..., 1 or 0.

B.3.22 TotalVibrationL total vibrational angular momentum. It is the sum of all angular momenta ±li associated to degenerate vibrations: lν = | Pi(±li)|.

B.3.23 VibronicAngularMomentumK is the sum of the total vibrational angular momentum lν and of the electronic orbital momentum about the internuclear axis Λ: K = |± lν ± Λ|; here K, lν, Λ are unsigned quantities. This is used for linear polyatomic molecules. (see p. 25 Volume III of Herzberg (1991), and REC. (recommendation) 17 of Mulliken (1955))

B.3.24 VibronicAngularMomentumP is the sum of the total vibrational angular momentum lν and of the total electronic orbital momentum about the internuclear axis Ω: P = | ± lν ± Ω|; here P , lν, Ω are unsigned quantities. This is used for linear polyatomic molecules. (see p. 26 Volume III of Herzberg (1991), and REC. 18 of Mulliken, 1955)

B.3.25 RovibronicAngularMomentumP total resultant axial angular momentum quantum number including electron spin: P = |K+Σ|. (REC. 26 of Mulliken, 1955).

B.3.26 HinderedK1, HinderedK2

2 additional projection quantum numbers are necessary for internal free rotation of 2 parts of a molecule: “HinderedK1” and “HinderedK2”, such that the total rotational energy is given by: 2 2 2 F (N,K,k1,k2)= BN(N +1)−BK +A1k1 +A2k2 where N is TotalAngularMomentumN, K is TotalMolecularProjectionN, k1 is HinderedK1 and k2 is HinderedK2 (see p. 492, Volume II of Herzberg (1964)). B.4. Symmetries 113

B.4 Symmetries

B.4.1 PermutationSymmetry Its value is “a” or “s”. It classifies rovibrational or rovibronic levels of symmetrical linear molecules with respect to the exchange of sets of identical nuclei (Mulliken, 1955).

B.4.2 EfSymmetry gives the e/f symmetry of levels. Its values is “e” or “f” (Brown et al., 1975)

B.4.3 C2aSymmetry a behavior of rotational states of molecules with respect to the C2 symmetry operation. Its value can be modelled with “+” (+1) or “-” (-1). It will be used in combination with “c2cSymmetry” in order to distinguish the behaviors of rotational levels of asymmetric molecules. (Herzberg, T II, p 51)

B.4.4 C2bSymmetry b behavior of rotational states of molecules with respect to the C2 symmetry operation. Its value can be modelled with “+” (+1) or “-” (-1). It is used to distinguish rotational levels of symmetric top molecules.

B.4.5 C2cSymmetry c behavior of rotational states of molecules with respect to the C2 symmetry operation. Its value can be modelled with “+” (+1) or “-” (-1). It will be used in combination with “c2aSymmetry” in order to distinguish the behaviors of rotational levels of asymmetric molecules.

B.4.6 VibrationalSpeciesNotation symmetry species symbol for pure vibrational levels when relevant.

B.4.7 VibronicSpeciesNotation symmetry species symbol for vibronic levels when relevant.

B.4.8 RoVibrationalSpeciesNotation symmetry species symbol for rovibrational levels when relevant.

B.4.9 RoVibronicSpeciesNotation symmetry species symbol for rovibronic levels when relevant. Note on notation for symmetry species symbols: they might be composed of letters (Σ, Π, etc.., A, B, ..) with left superscript and right superscript/subscript. 114 Appendix B. List of quantum numbers and symmetry identifications 115

Appendix C

Description of couplings for molecular Physics

C.1 Coupling of Rotation and Electronic motion in diatomic molecules

Only the most common cases are described below. We give the vector diagrams as they can be found and explained in Townes (1975) (p. 176) or in Herzberg (1950) (p. 218).

C.1.1 Hund’s case (a)

J R

Ω

ΛΣ L S Levels are identified by (J, Ω)

Symbol in Diagram Molecular Quantum Numbers in XSAMS J TotalAngularMomentumJ Ω TotalmolecularProjectionJ Λ TotalMolecularProjectionL Σ TotalMolecularProjectionS S (not defined) TotalSpinMomentumS R is pure rotation - not necessary L (not defined) is the total electronic orbital angular momentum 116 Appendix C. Description of couplings for molecular Physics

C.1.2 Hund’s case (b)

S

J N R

Λ L

Levels are identified by (J , N)

Symbol in Diagram Molecular Quantum Numbers in XSAMS J TotalAngularMomentumJ N TotalAngularMomentumN Λ TotalMolecularProjectionL S TotalSpinMomentumS R is pure rotation - not necessary L (not defined) is the total electronic orbital angular momentum

C.2 Coupling Schemes for Magnetic Hyperfine Structure (di- atomic molecules other than 1Σ

These coupling schemes are described in Townes (1975) (p. 196). They are classified according to Hund’s scheme. The subscript α indicates that the nuclear spin is most strongly coupled to the molecular axis and a subscript β indicates that the nuclear spin is not coupled to the molecular axis but to some other vector. C.2. Coupling Schemes for Magnetic Hyperfine Structure (diatomic molecules other than 1Σ117

C.2.1 Case (aα)

F R Ω

ΩI ΛΣ I L S

Levels are identified by (F , Ω)

Symbol in Diagram Molecular Quantum Numbers in XSAMS F TotalAngularMomentumF Ω TotalmolecularProjectionF Λ TotalMolecularProjectionL Σ TotalMolecularProjectionS S (not defined) TotalSpinMomentumS I (not defined) nuclearSpin or ISum ΩI is molecular projection of I - not necessary R is pure rotation - not necessary L (not defined) is the total electronic orbital angular momentum 118 Appendix C. Description of couplings for molecular Physics

C.2.2 Case (aβ)

I

F

J R Ω

ΛΣ L S

Levels are identified by (F , J, Ω). In XSAMS schema, F points to J and I; if I is ISum, I points to two nuclear spins defined in AtomNType.

Symbol in Diagram Molecular Quantum Numbers in XSAMS F TotalAngularMomentumF J TotalAngularMomentumJ Ω TotalmolecularProjectionJ I nuclearSpin or ISum Λ TotalMolecularProjectionL Σ TotalMolecularProjectionS R is pure rotation - not necessary L (not defined) is the total electronic orbital angular momentum S (not defined) TotalSpinMomentumS C.2. Coupling Schemes for Magnetic Hyperfine Structure (diatomic molecules other than 1Σ119

C.2.3 Case (bβN )

S I F F1

N R

Λ L

Levels are identified by (F , F1, N). In XSAMS schema, F points to F1 and S; F1 points to N and I; if I is ISum, I points to two nuclear spins defined in AtomNType.

Symbol in Diagram Molecular Quantum Numbers in XSAMS F TotalAngularMomentumF F1 IntermediateHyperfineAngularMomentumF N TotalAngularMomentumN I nuclearSpin or ISum S TotalSpinMomentumS Λ TotalMolecularProjectionL R is pure rotation - not necessary L (not defined) is the total electronic orbital angular momentum 120 Appendix C. Description of couplings for molecular Physics

C.2.4 Case (bβS)

S F2 I F

N R

Λ L

Levels are identified by (F , F2, N). In XSAMS schema, F points to F2 and N; F2 points to S and I; if I is ISum, I points to two nuclear spins defined in AtomNType.

Symbol in Diagram Molecular Quantum Numbers in XSAMS F TotalAngularMomentumF F2 IntermediateHyperfineAngularMomentum N TotalAngularMomentumN I nuclearSpin or ISum S TotalSpinMomentumS Λ totalMolecularProjectionL R is pure rotation - not necessary L (not defined) is the total electronic orbital angular momentum C.3. Example of hyperfine coupling by two nuclei 121

C.2.5 Case (bβJ )

I S F J

N R

Λ L Levels are identified by (F , J, N). In XSAMS schema, F points to J and I; if I is ISum, I points to two nuclear spins defined in AtomNType.

Symbol in Diagram Molecular Quantum Numbers in XSAMS F TotalAngularMomentumF J TotalAngularMomentumJ N TotalAngularMomentumN Λ TotalMolecularProjectionL S TotalSpinMomentumS I nuclearSpin or ISum R is pure rotation - not necessary L (not defined) is the total electronic orbital angular momentum

C.3 Example of hyperfine coupling by two nuclei

This example is treated in Gordy (1984) (p. 423): vector diagram of the nuclear quadrupole interaction by two nuclei in a molecule with the coupling of I1 (nucleus 1) assumed to be stronger than that of I2 (nucleus 2). 122 Appendix C. Description of couplings for molecular Physics

Levels are identified by (F , F1, J). In XSAMS schema, F points to F1 and I2; F1 points to J and I1.

Symbol in Diagram F TotalAngularMomentumF F1 IntermediateHyperfineAngularMomentum J TotalAngularMomentumJ I1 nuclearSpin I2 nuclearSpin 123

Appendix D

List of the XSAMS Process Codes

Version 0.2, October 2008

D.1 Introduction

In order to facilitate searching and sorting XSAMS files or blocks of data within a file, a classification scheme is defined to provide standard definitions for the fundamental process that is being described (e.g., the reflection of a particle from a surface or the excitation of an atomic state). The process codes are ”fundamental” in that they do not define the reactions to a great degree of detail that is carried out by specific elements of the overall schema. Rather, they provide a high level identification that can be used to aggregate similar data or provide a simple search point.

D.2 Process Codes

The following table defines the fundamental reactant codes. The process codes embody a high level description and a much more complete definition of the process that data pertain to is contained in the elements of the full schema. Processes are split into two categories: collisions (electron and heavy particle collisions) and particle surface interactions (PSI). Within each category, the codes are intended for use with any reactant. For example, a single process code is used to describe elastic scattering whatever is the projectile (electron, photon, atom, ion or molecule). This approach has been taken not only for economy but because an exhaustive list of processes involving elementary particles, atoms, molecules, and solids is not likely possible. Even if it were, using it would be cumbersome in that some non-intuitive coding would be necessary, for example, to encode inverse bremstrahlung, sublimation of water from a dust grain, a production of an atomic inner shell vacancy with a subsequent Coster-Kronig decay, etc. Multiple process codes can be given in order to build more complex descriptions from the fundamental processes, e.g., charge transfer + ionization in ion-atom collisions could be described by the code for ionization (liberation of an electron from the target or projectile to the continuum) and the code for charge transfer (the transfer of an electron from one collision partner to another). This combining of individual codes avoids the need for a code for all possible combinations of processes that are at least relatively common, e.g., dissociative recombination simply has the codes for dissociation and for recombination. Other examples of combinations of codes are given in the final table. 124 Appendix D. List of the XSAMS Process Codes

D.2.1 Atomic and Molecular Collisions

Code Name Description

phem Photon emission Emission of a photon or photons from a reactant (e.g.,. atom, molecule, surface), fluorescence phab Photon absorption Absorption of a photon or photons from a reactant (e.g., atom, molecule, surface) phsc Photon scattering Scattering of a photon or photons by a reactant elas Elastic scattering Scattering of one reactant from another without change of state or energy, including related processes such as momentum transfer inel Inelastic scattering Scattering of one reactant from another with change of state or energy. This code is provided in case none of the other specific inelastic codes are applicable or appropriate (e.g., energy or spin transfer reactions, projectile energy loss) exci Excitation Excitation from a lower to higher state of any fundamental reactant, e.g., electron-impact excitation of an atom, photoexcitation of a molecule to a higher ro-vibrational state deex De-excitation Induced or spontaneous transition from a higher state to a lower state, e.g., vibrational de-excitation in atom-diatom scattering ioni Ionization Removal of an electron from any reactant tran Charge transfer Transfer of an electron from one "center" (atomic ion, atom, molecule, etc.) to another exch Electron exchange The exchange of an electron with another electron (most commonly in electron-impact processes) reco Recombination Capture of an electron by an atomic or molecular ion, e.g., in dissociative recombination, dielectronic recombination, or radiative recombination elat Electron attachment The formation of a negative ion by electron attachment eldt Electron detachment The removal of the weakly bound electron of a negative ion by photon impact or collision with another particle such as an electron or surface asso Association Association of two (or more) reactants, typically neutrals, collisionally, or radiatively diss Dissociation The splitting of two (or more) reactants e.g., via electron-impact of a molecule, photodissociation, molecular break-up on a surface intr Interchange The exchange of a heavy particle (atom, ion) in a reaction, e.g., D + H2 → DH + H chem Chemical reaction The exchange of atoms or groups of atoms in chemical reactions, e.g., C + 2O → CO2 + heat D.2. Process Codes 125

D.2.2 Particle Solid Interactions

Code Name Description

sure Reflection The elastic or inelastic reflection of a reactant from a surface suem Emission or erosion Any form of erosion of a surface, e.g., physical or chemical sputtering, etching, sublimation, emission of particle or macroscopic pieces, desorption, secondary electron emission sudp Deposition Absorption of particles by a surface, sticking, surface implantation such Change Change of the composition or properties of a surface induced by any reactant sope Penetration The penetration of a reactant into a solid, characterized by the change of energy, e.g., stopping, straggling, energy loss, range, charge state equilibrium, or change of structure, e.g., trapping, diffusion, deep implantation

D.2.3 Combination of Processes The following table gives examples of the use of the fundamental process codes to describe more complex but still common processes. Some simply fall within the broad scope of one of the fundamental codes and others can be described by use of multiple codes.

UNDER CONSTRUCTION

Common Name Codes Description

Penning ionization asso + ioni Association of atoms with ionization Transfer ionization tran + ioni Charge transfer between and ion and an atom, for example, with ionization Transfer excitation tran + exec Charge transfer with excitation Stripping ioni Ionization of the projectile in a collision of an ion or atom with an atom, molecule, or solid Dissociative recombination diss + reco Dielectronic recombination reco Auger ionization exci + ioni Spin-flip inel photoionization ioni Three-body recombination reco Superelastic scattering inel Surface catalysis sure + chem Stark shift Line broadening Bremsstrahlung Compton scattering 126 Appendix D. List of the XSAMS Process Codes 127

Appendix E

List of the IAEA DCN codes

E.1 Structure and Spectra

SUBCATEGORY CODE

General SGN Line Broadening, Shapes and Shifts SLS Interatomic Potentials SIA Polarizabilities, Electric Moments SPM Energy Levels and Wavelengths SEW Transition Probabilities and Oscillator Strengths STP Potential Curves and Structure of Molecules SSM Dynamic Polarizability SDP Infrared Spectra SIR Visible Spectra SVS UV/VUV/XUV Spectra SUV X-Ray Spectra SXR Rotational Spectra SRS Vibrational Spectra SVB Autoionization SAI Autodetachment SAD Autodissociation SDS Magnetic Moments SMM Hyperfine Structure SHF Isoelectronic Sequences SIE Forbidden Transitions SFT QED Effects SQE Relaxation Processes SRP Ionization Potentials SIP Rydberg States SRY 128 Appendix E. List of the IAEA DCN codes

E.2 Electron-Heavy-Particle Interactions

SUBCATEGORY CODE PROCESS

General EGN Angular Scattering EAS Bremsstrahlung EBS e+A → e+A+hν Deexcitation EDX e+A∗ → e+A Elastic Scattering EEL e+A → e+A Line Broadening, Shapes and Shifts ELB Total Scattering ETS Detachment EDT e+A− → A+2e Fluorescence EFL Excitation EEX e+A → e+A∗ Change of Excitation EEX Ionization EIN e+A → e+A++e Multiple Ionization EMI e+A → A+n+(n+1)e Negative Ion Formation ENI e+A → A− Momentum Transfer EMT Transport CS’s (momentum,...) EMT Unknown Products EUP Depolarization, Change of Polarization EDP Creation of an ion pair (positive-negative) EIP e+AB+ →A−+B− Recombination (general) ERC A+q+e → A+(q−1) Radiative Recombination ERR e+A+ → A+hν Dielectronic Recombination ERD e+A+ → A∗∗ →A∗+hν+e 3-body Recombination ERT e+e+A+ → A+e e-i-o Recombination ERO e+A++B → A+B Dielectronic Capture EDC e+A+ → A∗∗ Dissociation EDS e+AB → e+A+B Dissociative Recombination EDR e+AB+ → A+B Dissociative Attachment EDA e+AB → A+B− Dissociative Excitation EDE e+AB → A∗+B+e Dissociative Ionization EDI e+AB → A++B+2e E.3. Photon-Particle and Field-Particle Interactions 129

E.3 Photon-Particle and Field-Particle Interactions

SUBCATEGORY CODE PROCESS

General PGN Total Absorption, Scattering PTS Photodissociation PDS hν+AB → A+B Elastic Scattering PES hν+A → h→+A Multiphoton Absorption (excitation and ionization) PMA nhν+A → A∗(A+) Photodetachment PDT A+B → AB+hν Fluorescence PFL Photoexcitation PEX hν+A → A∗ Photoionization PIN hν+A → A++e Free-Free Absorption or Inverse Bremsstrahlung PFF hν+e+A → e+A Effective Absorption, Total Diffusion PEA True Absorption PTA Angular Diffusion (scattering) PAD Elastic Diffusion (Thomson, Rayleigh) PED Non-linear Effects PNL Emission of Line PLE Zeeman Effect PZE Stark Effect PSE General Electromagnetic Field PGF Interaction with Time-Varying Fields PTF 130 Appendix E. List of the IAEA DCN codes

E.4 Heavy-Particle Interactions

SUBCATEGORY CODE PROCESS

General HGN Association HAS A+B → AB Line Broadening, Shapes and Shifts HLB Dissociation HDS A+BC → A+B+C Deexcitation HDX A∗+B → A+B Elastic Scattering HES A+B → A+B Charge Transfer HCX A++B → A+B+, A−+B → A+B− Unknown Products HUP Angular Scattering HAS Interchange Reactions HIR A+BC → AB+C Inelastic Energy Losses HEL Energy Transfer HET Interaction Potentials HIP Recombination HRC Total Scattering HTS Detachment HDT A+B− → A+B+e Fluorescence HFL Excitation HEX A+B → A∗+B Ionization HIN A+B → A+B++e Penning Ionization HPN A∗+B → A+B++e Stripping (of projectile) HST A+B → A++B+e Attenuation HAT Excitation Transfer HXT A∗+B → A+B* Associative Interchange Reactions HAI Dissociative Interchange Reactions HDI Dissociative Charge Transfer HDC A++BC → A+B++C Mutual Ion-Ion Neutralization HMN A++B− → A+B E.5. Particle-Matter Interactions 131

E.5 Particle-Matter Interactions

SUBCATEGORY CODE

General MGN Accomodation MAC Adsorption MAD Chemical Reactions MCR Desorption MDE Reemission MRE Reflection MRF Surface Damage MSD Secondary Electron Emission MSE Radiation Induced by Particle Impact on Surfaces MIR Neutralization, Ionization, Dissociation MNE Sputtering MSP Radiation-Enhanced Sublimation MRS Trapping, Detrapping MTD Photoelectric Ejection of Electrons MPE Energy Loss and Stopping Power MEL Particle Range MPR Multiple Scattering MMS Charge State Population MCP Excited State Population MEP Reflection of Heavy Particles from Surfaces MRH Reflection of Electrons from Surfaces MRL 132 Appendix E. List of the IAEA DCN codes

E.6 Data Compilations

SUBCATEGORY CODE

General DGN Electron-Heavy Particle Interactions DEH Heavy Particle-Heavy Particle Interactions DHH Photon-Particle and Field-Particle Interactions DPF Structure and Spectra DSS Transport Properties DTP Particle-Matter Interactions DPM

E.7 Bibliography

SUBCATEGORY CODE

General BGN Electron-Heavy Particle Interactions BEH Heavy Particle-Heavy Particle Interactions BHH Photon-Particle and Field-Particle Interactions BPF Structure and Spectra BSS Transport Properties BTP Particle-Matter Interactions BPM BIBLIOGRAPHY 133

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