CCCBDB listing of experimental data page 2

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Property	Value	Uncertainty	units	Reference
Hfg(298.15K)	583.86	22.00	kJ mol^-1	Gurvich
Hfg(0K)	580.00	22.00	kJ mol^-1	Gurvich
Entropy (298.15K)	238.00		J K^-1 mol^-1	Gurvich
Integrated Heat Capacity (0 to 298.15K)	10.30		kJ mol^-1	Gurvich
Heat Capacity (298.15K)	36.26		J K^-1 mol^-1	Gurvich

Mode Number	Symmetry	Frequency			Intensity			Comment	Description
Mode Number	Symmetry	Fundamental(cm^-1)	Harmonic(cm^-1)	Reference	(km mol^-1)	unc.	Reference	Comment	Description
1	Σ_g	507	511	VEEL5

Description	Value	unc.	Connectivity				Reference	Comment
Description	Value	unc.	Atom 1	Atom 2	Atom 3	Atom 4	Reference	Comment
rSiSi	2.246		1	2			1979HUB/HER	re

Atom	x (Å)	y (Å)	z (Å)
Si1	0.0000	0.0000	0.0000
Si2	0.0000	0.0000	2.2460

	Si1	Si2
Si1		2.2460
Si2	2.2460

	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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Energy (cm^-1)	Degeneracy	reference	description
0	3	1979HUB/HER	³Σ_g
669	6	1991Kit/Chi:1441	¹Σ_g
3509	2	1991Kit/Chi:1441
4783	2	1991Kit/Chi:1441
5138	1	1991Kit/Chi:1441
9000	1	Gurvich
24428.98	3	Gurvich

State	Config	State description	Conf description	Exp. min.	Dipole (Debye)				Reference	comment	Point Group	Components
State	Config	State description	Conf description	Exp. min.	x	y	z	total	Reference	comment	Point Group	dipole	quadrupole
1	1	³Σ_g	D_∞h	True				0.000	NSRDS-NBS10		D_∞h	0	1
2	1	¹Σ_g	D_∞h	True							D_∞h	0	1

squib	reference	DOI
1979HUB/HER	Huber, K.P.; Herzberg, G., Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules, Van Nostrand Reinhold Co., 1979	10.1007/978-1-4757-0961-2
1991Kit/Chi:1441	TN Kitsopoulos, CJ Chick, Y Zhao, DM Neumark "Study of low-lying electronic states of Si2 and Si2- using negative ion photodetachment techniques" J. Chem. Phys. 95(3), 1441, 1991	10.1063/1.461057
2007Iri:389	KK Irikura "Experimental Vibrational Zero-Point Energies: Diatomic Molecules" J. Phys. Chem. Ref. Data 36(2), 389, 2007	10.1063/1.2436891
Gurvich	Gurvich, L.V.; Veyts, I. V.; Alcock, C. B., Thermodynamic Properties of Individual Substances, Fouth Edition, Hemisphere Pub. Co., New York, 1989
NSRDS-NBS10	R. D. Nelson Jr., D. R. Lide, A. A. Maryott "Selected Values of electric dipole moments for molecules in the gas phase" NSRDS-NBS10, 1967	10.6028/NBS.NSRDS.10
VEEL5	M.E. Jacox, Vibrational and Electronic Energy Levels of Polyatomic Transient Molecules, J. Phys. Chem.Ref. Data, Monograph 3 (1994) (updated data in NIST Chemistry Webbook - http://webbook.nist.gov/chemistry/
webbook	NIST Chemistry Webbook (http://webbook.nist.gov/chemistry)	10.18434/T4D303

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Experimental data for Si2 (Silicon diatomic)

Experimental data for Si₂ (Silicon diatomic)