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State	Conformation	minimum conformation	conformer description	state description
1	1	no	D*H	¹Σ_G
1	2	no	C2H	¹A_G
1	3	yes	C2V	¹A₁
1	4	no	CS	¹A^'

	hartrees
Energy at 0K	-579.280395
Energy at 298.15K
HF Energy	-578.881678
Nuclear repulsion energy	66.854945

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	Σ_g	2368	2266
2	Σ_g	742	710
3	Σ_u	2378	2275
4	Π_g	522i	500i
4	Π_g	522i	500i
5	Π_u	421	403
5	Π_u	421	403

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	0.000	0.992
Si2	0.000	0.000	-0.992
H3	0.000	0.000	2.448
H4	0.000	0.000	-2.448

	Si1	Si2	H3	H4
Si1		1.9845	1.4558	3.4404
Si2	1.9845		3.4404	1.4558
H3	1.4558	3.4404		4.8962
H4	3.4404	1.4558	4.8962

All results from a given calculation for Si₂H₂ (disilyne)

using model chemistry: QCISD(T)=FULL/cc-pVTZ

States and conformations

Conformer 1 (D*H)

Conformer 2 (C2H)

Conformer 3 (C2V)

Conformer 4 (CS)

	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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	hartrees
Energy at 0K	-579.310672
Energy at 298.15K
HF Energy	-578.907522
Nuclear repulsion energy	63.741959

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	A_g	2209	2114
2	A_g	616	589
3	A_g	569	544
4	A_u	127	122
5	B_u	2201	2106
6	B_u	223	213

Atom	x (Å)	y (Å)
Si1	0.000	1.057
Si2	0.000	-1.057
H3	1.220	1.910
H4	-1.220	-1.910

	Si1	Si2	H3	H4
Si1		2.1144	1.4885	3.2084
Si2	2.1144		3.2084	1.4885
H3	1.4885	3.2084		4.5330
H4	3.2084	1.4885	4.5330

	hartrees
Energy at 0K	-579.339533
Energy at 298.15K
HF Energy	-578.950197
Nuclear repulsion energy	64.810030

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	A₁	1657	1586
2	A₁	930	890
3	A₁	529	506
4	A₂	1165	1114
5	B₁	1575	1508
6	B₂	1232	1179

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.108	-0.051
Si2	0.000	-1.108	-0.051
H3	0.986	0.000	0.720
H4	-0.986	0.000	0.720

	Si1	Si2	H3	H4
Si1		2.2156	1.6714	1.6714
Si2	2.2156		1.6714	1.6714
H3	1.6714	1.6714		1.9713
H4	1.6714	1.6714	1.9713

	hartrees
Energy at 0K	-579.323747
Energy at 298.15K
HF Energy	-578.928089
Nuclear repulsion energy	65.001464

	Si1	Si2	H3	H4
Si1		2.1213	1.7217	3.5595
Si2	2.1213		1.6352	1.4865
H3	1.7217	1.6352		2.5316
H4	3.5595	1.4865	2.5316

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)
1	A'	2209	2114
2	A'	1674	1602
3	A'	1131	1082
4	A'	618	591
5	A'	463	443
6	A"	212	203

Atom	x (Å)	y (Å)
Si1	0.060	-1.145
Si2	0.060	0.976
H3	-1.240	-0.016
H4	-0.426	2.381

All results from a given calculation for Si2H2 (disilyne)

using model chemistry: QCISD(T)=FULL/cc-pVTZ

States and conformations

Conformer 1 (D*H)

Conformer 2 (C2H)

Conformer 3 (C2V)

Conformer 4 (CS)

All results from a given calculation for Si₂H₂ (disilyne)