DOCSLIB.ORG

Redalyc.The Role of Nd3+ in the Population Inversion Between 1G4 and 3H6 States of Tm3+ in Yb:Nd:Tm:YLF Crystal

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Redalyc.The Role of Nd3+ in the Population Inversion Between 1G4 and 3H6 States of Tm3+ in Yb:Nd:Tm:YLF Crystal Exacta ISSN: 1678-5428 [email protected] Universidade Nove de Julho Brasil Henriques Librantz, André Felipe; Coronato Courrol, Lilia; Gomes, Laércio; Ranieri, Izilda Marcia; Baldochi, Sonia Lícia The role of Nd3+ in the population inversion between 1G4 and 3H6 states of Tm3+ in Yb:Nd:Tm:YLF crystal Exacta, vol. 5, núm. 1, janeiro-junho, 2007, pp. 113-118 Universidade Nove de Julho São Paulo, Brasil Available in: http://www.redalyc.org/articulo.oa?id=81050111 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Artigos The role of Nd+ in the population 1 + inversion between G4 and H states of Tm in Yb:Nd:Tm:YLF crystal 1 André Felipe Henriques Librantz Professor pesquisador – Uninove; Pesquisador colaborador – Ipen-USP. São Pauilo – SP [Brasil] [email protected] Lilia Coronato Courrol Professora pesquisadora – Unifesp. São Pauilo – SP [Brasil] [email protected] Laércio Gomes Pesquisador – Ipen-USP. São Pauilo – SP [Brasil] [email protected] Izilda Marcia Ranieri Pesquisador – Ipen-USP. São Pauilo – SP [Brasil] [email protected] Sonia Lícia Baldochi Pesquisador – Ipen-USP. São Pauilo – SP [Brasil] [email protected] In this paper, we present the energy transfer rates of YLF:Yb: Tm:Nd system, identifying the most important processes that lead to the thulium blue upconversion emission under excitation around 792 nm. The calculation of the rate equations system based on numerical method using Runge-Kutta method was 1 employed for analyzing the population inversion between G4 3 3+ and H4 states of Tm . Population inversion was achieved only in Yb:Nd:Tm doped YLF crystal, which exhibits a pumping rate threshold of 620 s-1. The Nd3+ absorption near 792 nm is very important because the excitation is rapidly transferred to Yb3+, that also interacts with Tm3+. Key words: Tm3+ blue emission upconversion. Numerical simulation. Exacta, São Paulo, v. 5, n. 1, p. 113-118, jan./jun. 2007. 11 1 Introduction composition of 1.02 LiF: 1 LnF3. LiF powder (Al- pha-Johnson Matthey, 99.9%) was zone-refined Thulium-doped materials generate blue laser before it was added to the mixture. emission through the nonlinear conversion of ra- The studied crystal was grown by the Czo- diation from the infrared into visible range (GOS- chralski method using diameter automatic control, NELL et al., 2003), after various cross-relaxation with growing rate of 1.30 mm/h and rotation rate (CR) and excited state absorption (ESA) processes of 15 rpm for the <100>-oriented boule. During (CHADEYRON et al., 2002). Particularly, blue la- the process, the atmosphere inside the Czochral- ser is important in the compact disc industry, opti- ski furnace was composed by Ar (1.4 bar) and CF4 cal storage systems, color displays and in new med- (0.2 bar). ical and dentistry applications and in atmospheric The YLF:Yb:Tm:Nd crystal with 60mm in and physics research (MEIJERINK et al., 2002). length and 20mm in diameter was used. Samples LiYF4 (YLF) crystals doped with thulium were cut from this crystal (middle). Nd concen- (Tm3+) and also co-doped with ytterbium (Yb3+) tration was measured to be 1 mol%. The samples (BASS et al., 1995; CASSANJES et al., 2002) are were cut and polished with 2 mm thickness. well-known as active media that generate stimu- The absorption spectra of the glasses were lated radiation on a number of lines over a wide measured by using a spectrophotometer (Cary/ spectral range from 450 nm to 2350 nm, upon OLIS17D) operating in the range of 300-2000 selective laser, laser diode, and flash lamp pump- nm. For emission and lifetime measurements of ing (JOUBERT, 1999; BASS et al., 2004; GOMES the excited states of the Yb3+,Tm3+ and Nd3+ ions. et al., 2004). It was demonstrated that the addi- The sample was excited by laser radiation generat- tion of Nd3+ as a second sensitizer for YLF:Yb:Tm ed by tunable optical parametric oscillator (OPO), crystals improves the upconversion mechanism which was pumped by the second harmonic of a that gives rise to the Tm3+ blue emission in 475 nm Q-switched Nd-YAG laser (Brilliant B from Qu- (BALDOCHI et al., 2005). antel) of 4 ns and 10 HZ; and observed by a 0.25 In this work, we compare the blue thu- m Kratos monochromator, EGG Bos car Proces- lium emission obtained after pumping the YLF: sor, EMI S-20 PMT and InSb 77K infrared detec- Yb(20mol%):Tm(0.5mol%):Nd(1%) crystal at two tor (Judson). different wavelengths: 792 nm or 960 nm. All the fluorescence decay times were mea- sured at 300 K. In order to isolate these lumines- cence signals, band pass filters with ~80 % trans- 2 Experimental setup mission at 1200 and 2000 nm (each with a half width of 15 nm and an extinction coefficient of The rare earth fluorides were prepared from ~10-5) was used. pure oxide powders (Alpha-Johnson Matthey, 99.99%) by hydrofluorination at high temperature in HF atmosphere. The powder was contained in Results and discussions a cylindrical platinum boat, which was inserted in a sealed platinum tube. The LiF-LnF3 (Ln=Y, Yb, YLF:Yb:Tm:Nd crystal has two main absorp- Nd, and Tm) mixture was melted using an open tions in the near infrared at ~960 nm (Yb3+) and platinum boat in the same atmosphere, with a near 792 nm due to Nd3+ and Tm3+ ions, which 114 Exacta, São Paulo, v. 5, n. 1, p. 113-118, jan./jun. 2007. Artigos 20 Detector InSb ou Yb:Nd:Tm:YLF fotomultiplicadora Emission: 1 µm Nd 3+ (4 F ) 15 3/2 Excitation at 792 nm Monocromador ou filtro 10 Signal (arbit. units) 3+ 2 Yb ( F 5/2 ) 5 Lentes OPO GSH Nd:YAG Signal (arbit. units) Amostra 0 0 1 2 3 4 TimeTime (ms) Pré-amplificador Computador Box-car ou Figure 2: Emission decay curve (1.0mm) excited osciloscópio by pulsed laser at 792 nm in Yb:Tm:Nd:YLF crystal Source: The authors. Figure 1: Schematic diagram of the experimental Yb:Tm:YLF setup 8 Emission at 1 µm Source: The authors. Excitation: 792 nm can be used for solid state laser system pumped by diode laser. The most intense absorption is near 4 960 nm due to high concentration of Ytterbium Signal (arbit. units) in the sample. Besides that, Neodymium absorp- Signal (arbit. units) tion at ~792 nm is approximately 8 times more 0 intense than Thulium absorption (at) due to the 0 1 2 3 4 5 6 7 8 highest absorption cross section of Nd3+ in the π TimeTime (ms) polarization. Figure : Emission decay curve (1.0mm) excited When YLF sample containing Tm3+ co- by pulsed laser at 792 nm in Yb:Tm:YLF crystal Source: The authors. doped with Yb3+ and Nd3+, excited at 792 nm, a strong blue emission is observed with maximum dicates that Nd ions significantly contribute to the at 475 nm, due to the transition 1G T 3H . It is 4 6 population of 1G excited level. more intense than the red emission at ~ 650 nm. 4 Figure 2 shows the 1.06 m emission, in which the µ .1 Rate equations system fast component is due to Nd (4F ) T Yb transfer 3/2 Figure 4 shows a simplified energy level (process b). Figure 3 shows the 1.06µm emission scheme of the (Yb3+, Tm3+, Nd3+) system consid- 3+ from Yb indirectly excited by Tm T Yb transfer ered for continuous laser pumping at 797nm. (process d). According to the energy levels diagram of We observe also that the Nd(1 mol%) effect Figure 4, the following rate equations were de- in the Yb:Nd:Tm:YLF crystal causes an enhance- rived for Yb:Nd:Tm:YLF system under continu- ment of the Tm3+ blue emission due to the Nd(4F ) 3/2 ous laser pumping at 792 nm. The n1 and n2 are 3 3+ T Tm( H4) (process h, seen in Figure 3), which in- the Yb population, n3, n4, n5 and n6 refers to the Exacta, São Paulo, v. 5, n. 1, p. 113-118, jan./jun. 2007. 11 Table 1: Rate equation of the system and spectroscopic parameters dn1 n2 = + gn2n5 + en3n3 - dn1n5 + fn2n4 - bn1n8 + cn2n7 dt t2 dn2 n2 = + dn1n5 - gn2n5 - en2n3 - fn2n4 + bn1n8 - cn2n7 dt t2 dn n b b 3 = - R n + 4 + 53 n + 63 n + dn n - en n p 3 t 5 6 1 5 2 3 dt 4 t5 t6 dn n b b 4 = - 4 + 54 n + 64 n - fn n + en n dt t t 5 t 6 2 4 2 3 Figure 4: Energy levels scheme and energy 4 5 6 transfer mechanisms of Yb/Tm/Nd system. dn n b 5 = - R n + 5 + 65 n - dn n - gn n - hn n + fn n Continuous line (up) 797 nm excitation, dashed dt p 3 t t 6 1 5 2 5 5 8 2 4 line (up) 965 nm excitation. Dash dot line (down) 5 6 blue thulium emissions. Dot lines (up and down) dn n 6 = - 6 + hn n + gn n Yb emission and cross relaxation processes 5 8 2 5 dt t6 Source: The authors. dn7 n8 = - 7.8 Rpn7 + + bn1n8 + hn5n8 dt t8 3+ 3+ Tm and n7, n8, are the Nd populations, in which dn n 8 = 7.8 R n - 8 - bn n - hn n dt p 7 t 1 8 5 8 n1+n2= 20 mol%, n3+n4+n5+ n6=0.5 mol% and 8 n7+n8= 1mol%.
Load more

Recommended publications
  • Historical Development of the Periodic Classification of the Chemical Elements
    THE HISTORICAL DEVELOPMENT OF THE PERIODIC CLASSIFICATION OF THE CHEMICAL ELEMENTS by RONALD LEE FFISTER B. S., Kansas State University, 1962 A MASTER'S REPORT submitted in partial fulfillment of the requirements for the degree FASTER OF SCIENCE Department of Physical Science KANSAS STATE UNIVERSITY Manhattan, Kansas 196A Approved by: Major PrafeLoor ii |c/ TABLE OF CONTENTS t<y THE PROBLEM AND DEFINITION 0? TEH-IS USED 1 The Problem 1 Statement of the Problem 1 Importance of the Study 1 Definition of Terms Used 2 Atomic Number 2 Atomic Weight 2 Element 2 Periodic Classification 2 Periodic Lav • • 3 BRIEF RtiVJiM OF THE LITERATURE 3 Books .3 Other References. .A BACKGROUND HISTORY A Purpose A Early Attempts at Classification A Early "Elements" A Attempts by Aristotle 6 Other Attempts 7 DOBEREBIER'S TRIADS AND SUBSEQUENT INVESTIGATIONS. 8 The Triad Theory of Dobereiner 10 Investigations by Others. ... .10 Dumas 10 Pettehkofer 10 Odling 11 iii TEE TELLURIC EELIX OF DE CHANCOURTOIS H Development of the Telluric Helix 11 Acceptance of the Helix 12 NEWLANDS' LAW OF THE OCTAVES 12 Newlands' Chemical Background 12 The Law of the Octaves. .........' 13 Acceptance and Significance of Newlands' Work 15 THE CONTRIBUTIONS OF LOTHAR MEYER ' 16 Chemical Background of Meyer 16 Lothar Meyer's Arrangement of the Elements. 17 THE WORK OF MENDELEEV AND ITS CONSEQUENCES 19 Mendeleev's Scientific Background .19 Development of the Periodic Law . .19 Significance of Mendeleev's Table 21 Atomic Weight Corrections. 21 Prediction of Hew Elements . .22 Influence
    [Show full text]
  • The Development of the Periodic Table and Its Consequences Citation: J
    Firenze University Press www.fupress.com/substantia The Development of the Periodic Table and its Consequences Citation: J. Emsley (2019) The Devel- opment of the Periodic Table and its Consequences. Substantia 3(2) Suppl. 5: 15-27. doi: 10.13128/Substantia-297 John Emsley Copyright: © 2019 J. Emsley. This is Alameda Lodge, 23a Alameda Road, Ampthill, MK45 2LA, UK an open access, peer-reviewed article E-mail: [email protected] published by Firenze University Press (http://www.fupress.com/substantia) and distributed under the terms of the Abstract. Chemistry is fortunate among the sciences in having an icon that is instant- Creative Commons Attribution License, ly recognisable around the world: the periodic table. The United Nations has deemed which permits unrestricted use, distri- 2019 to be the International Year of the Periodic Table, in commemoration of the 150th bution, and reproduction in any medi- anniversary of the first paper in which it appeared. That had been written by a Russian um, provided the original author and chemist, Dmitri Mendeleev, and was published in May 1869. Since then, there have source are credited. been many versions of the table, but one format has come to be the most widely used Data Availability Statement: All rel- and is to be seen everywhere. The route to this preferred form of the table makes an evant data are within the paper and its interesting story. Supporting Information files. Keywords. Periodic table, Mendeleev, Newlands, Deming, Seaborg. Competing Interests: The Author(s) declare(s) no conflict of interest. INTRODUCTION There are hundreds of periodic tables but the one that is widely repro- duced has the approval of the International Union of Pure and Applied Chemistry (IUPAC) and is shown in Fig.1.
    [Show full text]
  • To Ytterbium(II)
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 12-2008 The Use of Lanthanide Triflates as a Method for Reducing Ytterbium(III) to Ytterbium(II) Latasha Michelle Garrett University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Chemistry Commons Recommended Citation Garrett, Latasha Michelle, "The Use of Lanthanide Triflates as a Method for Reducing tterbium(III)Y to Ytterbium(II). " Master's Thesis, University of Tennessee, 2008. https://trace.tennessee.edu/utk_gradthes/378 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Latasha Michelle Garrett entitled "The Use of Lanthanide Triflates as a Method for Reducing tterbium(III)Y to Ytterbium(II)." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Chemistry. George Schweitzer, Major Professor We have read this thesis and recommend its acceptance: Ben Xue, Jamie Adcock Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a thesis written by Latasha Michelle Garrett entitled “The Use of Lanthanide Triflates as a Method for Reducing Ytterbium(III) to Ytterbium(II).” I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Master of Science, with a major in chemistry.
    [Show full text]
  • Periodic Table 1 Periodic Table
    Periodic table 1 Periodic table This article is about the table used in chemistry. For other uses, see Periodic table (disambiguation). The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers (numbers of protons in the nucleus), electron configurations , and recurring chemical properties. Elements are presented in order of increasing atomic number, which is typically listed with the chemical symbol in each box. The standard form of the table consists of a grid of elements laid out in 18 columns and 7 Standard 18-column form of the periodic table. For the color legend, see section Layout, rows, with a double row of elements under the larger table. below that. The table can also be deconstructed into four rectangular blocks: the s-block to the left, the p-block to the right, the d-block in the middle, and the f-block below that. The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table.
    [Show full text]
  • Page 1 of 2 Ytterbium (Yb)
    Ytterbium (Yb) - Chemical properties, Health and Environmental effects Page 1 of 2 Search : Go! Ytterbium - Yb Contact us Chemical properties of Ytterbium - Health effects of ytterbium - Environmental effects of ytterbium Atomic number 70 Atomic mass 173.04 g.mol -1 Electronegativity according to Pauling 1.1 Density 7 g.cm-3 at 20°C Melting point 824 °C Boiling point 1466 °C Vanderwaals radius unknown Ionic radius unknown Isotopes 9 Electronic shell [ Xe ] 4f14 6s2 Energy of second ionisation 602.4 kJ.mol -1 Energy of second ionisation 1172.3 kJ.mol -1 Energy of third ionisation 2472.3 kJ.mol -1 Standard potential - 2.27 V Jean de Marignac in Discovered by 1878 Ytterbium Ytterbium is a soft, malleable and rather ductile element that exhibits a bright silvery luster. A rare earth, the element is easily attacked and dissolved by mineral acids, slowly reacts with water, and oxidizes in air. The oxide forms a protective layer on the surface. Compounds of ytterbium are rare. Chemical Properties Find more sources/options for Chemical Properties Applications www.webcrawler.com Ytterbium is sometimes associated with yttrium or other related elements and is used in certain steels. Its metal could be used to help improve the grain refinement, strength, and other mechanical properties of stainless steel. Some ytterbium alloys have been used in dentistry. One ytterbium isotope has been used Cerium as a radiation source substitute for a portable X-ray machine when electricity was not available. Like other PIDC: US Service & rare-earth elements, it can be used to dope phosphors, or for ceramic capacitors and other electronic Quality at Chinese Prices devices, and it can even act as an industrial catalyst.
    [Show full text]
  • The Reduction of Ytterbium (III) to Ytterbium (II)
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 5-2007 The Reduction of Ytterbium (III) to Ytterbium (II) Amanda S. Jones University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Chemistry Commons Recommended Citation Jones, Amanda S., "The Reduction of Ytterbium (III) to Ytterbium (II). " Master's Thesis, University of Tennessee, 2007. https://trace.tennessee.edu/utk_gradthes/251 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Amanda S. Jones entitled "The Reduction of Ytterbium (III) to Ytterbium (II)." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Chemistry. George K. Schweitzer, Major Professor We have read this thesis and recommend its acceptance: Jamie L. Adcock, Michael J. Sepaniak Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a thesis written by Amanda Shirlene Jones entitled “The Reduction of Ytterbium (III) to Ytterbium (II).” I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree Master of Science, with a major in Chemistry.
    [Show full text]
  • Investigation of the First Ionization Potential of Ytterbium in Argonbuffer
    Vol. 49 (2018) ACTA PHYSICA POLONICA B No 3 INVESTIGATION OF THE FIRST IONIZATION POTENTIAL OF YTTERBIUM IN ARGON BUFFER GAS∗ P. Chhetria;b, C.S. Moodleyb;c, S. Raederb;d, M. Blockb;d;e F. Giacoppob;d, S. Götzb;d;e, F.P. Heßbergerb;d, M. Eibachb;f O. Kalejab;e;g, M. Laatiaouih, A.K. Mistryb;d T. Murböckb;d, Th. Walthera aTechnische Universität Darmstadt, 64289 Darmstadt, Germany bGSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany cUniversity of the Witwatersrand Braamfontein 2000, Johannesburg, South Africa dHelmholtzinstitut Mainz, 55099 Mainz, Germany eJohannes Gutenberg-Universität Mainz, 55099 Mainz, Germany f University of Greifswald, 17489 Greifswald, Germany gMax-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany hKatholieke Universiteit Leuven, 3000 Leuven, Belgium (Received January 9, 2018) One of the most important atomic properties influencing elements chem- ical behaviour is the energy required to remove its outermost electron: the first ionization potential (IP). The determination of this basic atomic prop- erty is challenging for the transfermium elements with Z > 100. Recently, Rydberg states have been observed in nobelium (No, Z = 102) inside a buffer gas cell. The buffer gas environment influences the energy of the Rydberg levels and thus the IP extracted from analysing the Rydberg se- ries. Therefore, laser resonance ionization spectroscopy in a buffer gas cell was employed to determine the IP of its chemical homologue, ytterbium (Yb, Z = 70) at different buffer gas pressures to characterize the system- atics arising from the buffer gas environment. DOI:10.5506/APhysPolB.49.599 1. Introduction Atomic structure studies of the heaviest elements with Z > 100 is one of the most interesting and challenging disciplines of atomic physics [1].
    [Show full text]
  • Periodic Table Part 1 Handout.Pdf
    Periodic Table Part 1 Name_______________________________ Period:________ 3 Learning Objective Using the terms given complete the diagram of 3 states of matter and phase changes Terms Solid Liquid Gas Condensation Vaporization Freezing Melting Periodic Table How do you read the periodic table? Science brings lots of work together and adds to understanding the Physical Universe John Newlands 1865 Dmitri Mendeleev 1869 Henry Mosley 1913 Horizontal rows are called _______________________________ Numbered _____________ Vertical columns are called _______________________________ Numbered ______________ 1 Classifying Elements based on Properties: How are the elements organized? Metals, Non-metals and Metalloids Class of Elements State of Matter (typical) Properties Examples of Elements Metals Metaloids Nonemetals Share with your neighbor the elements you selected as metals, non-metals or metalloids. Did your neighbor have some elements you did not include? Did you both agree with the identifications? 2 Element Entry Identification What is the Atomic Number? What is the average atomic mass? If Ag-108 is the most common isotopes. What are isotopes? The mass number is 108 so how many neutrons are there is Ag-108? How many protons do the following have? Calcium _____ Gold_____ Copper_____ Iron _____ How many electrons do the following have? Calcium ____ Gold____ Copper_____Uranium ______ Name of Group Group Examples Description of Properties (Metal, Nonmetal or Group # (symbols) Metalloid) and Facts alkali metals alkaline earth metals Boron group Nitrogen Group Oxygen Group Chacagon halogens noble gases transition metals lanthanides actinides 3 Directions: Answer the questions with the proper information using your notes and the periodic table. 1. Define a family. __________________________________________________________________ 2.
    [Show full text]
  • BNL-79513-2007-CP Standard Atomic Weights Tables 2007 Abridged To
    BNL-79513-2007-CP Standard Atomic Weights Tables 2007 Abridged to Four and Five Significant Figures Norman E. Holden Energy Sciences & Technology Department National Nuclear Data Center Brookhaven National Laboratory P.O. Box 5000 Upton, NY 11973-5000 www.bnl.gov Prepared for the 44th IUPAC General Assembly, in Torino, Italy August 2007 Notice: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. This preprint is intended for publication in a journal or proceedings. Since changes may be made before publication, it may not be cited or reproduced without the author’s permission. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or any third party’s use or the results of such use of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or subcontractors.
    [Show full text]
  • The Elements.Pdf
    A Periodic Table of the Elements at Los Alamos National Laboratory Los Alamos National Laboratory's Chemistry Division Presents Periodic Table of the Elements A Resource for Elementary, Middle School, and High School Students Click an element for more information: Group** Period 1 18 IA VIIIA 1A 8A 1 2 13 14 15 16 17 2 1 H IIA IIIA IVA VA VIAVIIA He 1.008 2A 3A 4A 5A 6A 7A 4.003 3 4 5 6 7 8 9 10 2 Li Be B C N O F Ne 6.941 9.012 10.81 12.01 14.01 16.00 19.00 20.18 11 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 3 Na Mg IIIB IVB VB VIB VIIB ------- VIII IB IIB Al Si P S Cl Ar 22.99 24.31 3B 4B 5B 6B 7B ------- 1B 2B 26.98 28.09 30.97 32.07 35.45 39.95 ------- 8 ------- 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.10 40.08 44.96 47.88 50.94 52.00 54.94 55.85 58.47 58.69 63.55 65.39 69.72 72.59 74.92 78.96 79.90 83.80 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5 Rb Sr Y Zr NbMo Tc Ru Rh PdAgCd In Sn Sb Te I Xe 85.47 87.62 88.91 91.22 92.91 95.94 (98) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 6 Cs Ba La* Hf Ta W Re Os Ir Pt AuHg Tl Pb Bi Po At Rn 132.9 137.3 138.9 178.5 180.9 183.9 186.2 190.2 190.2 195.1 197.0 200.5 204.4 207.2 209.0 (210) (210) (222) 87 88 89 104 105 106 107 108 109 110 111 112 114 116 118 7 Fr Ra Ac~RfDb Sg Bh Hs Mt --- --- --- --- --- --- (223) (226) (227) (257) (260) (263) (262) (265) (266) () () () () () () http://pearl1.lanl.gov/periodic/ (1 of 3) [5/17/2001 4:06:20 PM] A Periodic Table of the Elements at Los Alamos National Laboratory 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Lanthanide Series* Ce Pr NdPmSm Eu Gd TbDyHo Er TmYbLu 140.1 140.9 144.2 (147) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Actinide Series~ Th Pa U Np Pu AmCmBk Cf Es FmMdNo Lr 232.0 (231) (238) (237) (242) (243) (247) (247) (249) (254) (253) (256) (254) (257) ** Groups are noted by 3 notation conventions.
    [Show full text]
  • In the Classroom
    324 Chem. Educator 2001, 6, 324–332 The Periodic Table: An Eight Period Table For The 21st Centrury Gary Katz Periodic Roundtable, Cabot, VT 05647, [email protected] Received March 23, 2001. Accepted May 7, 2001 Abstract: Throughout most of the 20th century, an eight-period periodic table (also known as an electron- configuration table) was offered as an improvement over the ubiquitous seven-period format of wall charts and textbooks. The eight-period version has never achieved wide acceptance although it has significant advantages. Many observers have questioned the way helium is displayed in this format. Now, a reinterpretation of the relationship of the first-period elements to successive elements may help make the eight-period table an attractive choice for the 21st century. The Eight-Period Periodic Table: An Improved Display of journals have apparently been loath to accept any recent the Elements comment on the subject, despite the need for a fresh dialogue. This is partly due to the lack of new evidence to bolster the The periodic table of textbooks and wall charts is used in cause of the eight-period table and partly to the conviction of classrooms and laboratories around the world. This familiar editors and reviewers that the discussion of the format of the format, which we designate the seven-period table, (Figure 1) table is over, as if the case were closed. has become the standard periodic table for the natural sciences despite the fact that it has serious shortcomings, both Structuring the Eight-Period Table theoretical and pedagogical. By rearranging the table, (as shown in Figure 2) we can create a different format (Figure 3), Upholders of the seven-period tradition object to the way which is both modular and algorithmic, that is, one which helium is displayed at the top of group two.
    [Show full text]
  • Atomic Clocks Compared with Astounding Accuracy
    News & views Tropical ecosystems are large contributors 10. Ahlström, A., Schurgers, G., Arneth, A. & Smith, B. 351–372 (2005). to the global terrestrial carbon sink10, but they Environ. Res. Lett. 7, 044008 (2012). 14. Lawrence, D. M. et al. J. Adv. Model. Earth Syst. 11, 11. Norby, R. J. et al. New Phytol. 209, 17–28 (2016). 4245–4287 (2019). are notoriously under-studied. Field obser- 12. Lugli, L. F. et al. New Phytol. 230, 116–128 (2021). 15. Yu, L., Ahrens, B., Wutzler, T., Schrumpf, M. & Zaehle, S. vations are scarce and few manipulation 13. Ainsworth, E. A. & Long, S. P. New Phytol. 165, Geosci. Model Dev. 13, 783–803 (2020). experiments — such as CO2 enrichment or nutrient additions — have been carried out in Metrology these ecosystems11,12. Below-ground processes are particularly challenging to assess in the tropics, where the effects of multiple nutri- ent scarcities often come into play12. Terrer Atomic clocks compared and colleagues’ study provides a promising framework that can be elaborated to describe with astounding accuracy diverse plant–soil interactions in various terrestrial ecosystems in the future. Rachel M. Godun CO2-enrichment experiments generally last for just a few years, or just over a decade Three atomic clocks based on different atoms have been 13 at most . Such timescales are unlikely to compared with record accuracy. The findings bring a capture the effects of elevated CO2 levels on redefinition of the second a step closer and aid the search for plant mortality, plant-species composition and soil-carbon turnover time, all of which dark matter — an elusive component of the Universe.
    [Show full text]