Supplementary Material. Transferable Density Functional Tight Binding for Carbon, Hydrogen, Nitrogen, and Oxygen: Application to Shock Compression M

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Supplementary Material. Transferable density functional tight binding for carbon, hydrogen, nitrogen, and oxygen: Application to shock compression M. J. Cawkwella) and R. Perriot Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

a)Electronic mail: [email protected]

1 The lanl31 DFTB parameterization was developed by ﬁtting its adjustable parameters to reproduce the atomization energies and interatomic forces of the molecules listed in Tables I and II. Each molecule was distorted 20 - 40 times, as noted in Tables I and II, and its total energy and interatomic forces were calculated using density functional theory at the

B3LYP/cc-pVTZ level. The atoms were displaced from their equilibrium positions, xi, by distortions, Di, 0 xi = xi + Di (1)

where

Di = dmaxηini (2)

and dmax is the maximum displacement, η a random number in the interval [0, 1], and n a

randomly-oriented vector from the origin to a position on the unit sphere. dmax = 0.2 A,˚ was used to generated the databases of training and testing data.

2 TABLE I. Molecules used to train and test the lanl31 DFTB parameterization

Number Name Formula Number of distortions

1 Methane CH4 20

2 Ethane CH3CH3 20

3 Ethene CH2CH2 20 4 Ethyne CHCH 20

5 Propane CH3CH2CH3 20

6 Propene CH3CHCH2 20

7 Propyne CH3CCH 20

8 1-Butyne CHCCH2CH3 20

9 1,3 butadiene CH2CHCHCH2 20

10 Napthalene C10H8 20

11 2-butene (Z) CH3CHCHCH3 20

12 2-butene (E) CH3CHCHCH3 20

13 2-methylpropene CH2C(CH3)CH3 20

14 Anthracene C14H10 20

15 Butane CH3CH2CH2CH3 20

16 Phenanthrene C14H10 20

17 Benzene C6H6 20

18 Toluene C6H5CH3 20

19 Ethylbenzene C6H5CH2CH3 20

20 Metaxylene CH3C6H4CH3 20

21 Spiropentane C5H8 20

22 Cyclopropane C3H6 20

23 Cyclopentane C5H10 20

24 Cyclopropene C3H4 20 25 Isocyanic acid HNCO 20 26 Cyanic acid HOCN 20 27 Fulminic acid HCNO 20

28 Dimethylnitroamine C2H6N2O4 20

29 Nitrous oxide N2O 20 30 Nitrous acid HONO 20 31 Hydrogen cyanide HCN 20

32 Methyl amine CH3NH2 20

33 Dimethyl amine CH3NHCH3 20

34 Nitromethane CH3NO2 20

35 Nitrosamide H2N2O 20

36 Hydroxylamine NH2OH 20

37 Methyl nitrate CH3ONO2 20

38 Nitric acid HNO3 20

39 Nitrosomethane CH3NO 40

3 TABLE II. Molecules used to train and test the lanl31 DFTB parameterization

Number Name Formula Number of distortions

40 Nitrogen dimer N2 20

41 E-diazine N2H2 20

42 Hydrazine N2H4 20 43 Carbon monoxide CO 20

44 Carbon dioxide CO2 20

45 Formaldehyde CH2O 20

46 Methanol CH3OH 20

47 Dimethyl ether CH3OCH3 20 48 Hydroxycarbene HCOH 20

49 Ozone O3 20

50 Water H2O 20

51 Hydrogen peroxide H2O2 20

52 Nitrous acid isomer 1 HNO2 20

53 Dinitrogen pentoxide N2O5 20

54 Urea CO(NH2)2 20

55 Carbamic acid H2NCOOH 20

56 Formamide CHONH2 20

57 Formaldoxime CH2NOH 20 58 Hydroxymethylimine HOCHNH 20

59 1,2-oxaziridine CNOH3 20

60 Nitromethane isomer 1 HOCH2NO 20 61 Nitromethane isomer 2 OCHNHOH 20 62 Nitromethane isomer 3 HONCHOH 20

63 Hydrogen dimer H2 32

64 Pentaerythritol tetranitrate C5H8(ONO2)4 32

65 1,3,5-Trinitro-1,3,5-triazinane C3H6N6O6 32

66 1,3,5-triamino-2,4,6-trinitrobenzene C6H6N6O6 32

67 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane C6H6N12O12 32