	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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All results from a given calculation for Si₂H₄ (Disilene)

using model chemistry: B1B95/cc-pVTZ

19 10 17 12 22

States and conformations

State	Conformation	minimum conformation	conformer description	state description
1	1	no	D2H	¹A_G
1	2	yes	C2H	¹A_G
1	3	no	C2V	¹A₁

Conformer 1 (D2H)

Jump to S1C2 S1C3

Energy calculated at B1B95/cc-pVTZ

	hartrees
Energy at 0K	-581.383505
Energy at 298.15K
HF Energy	-581.383505
Nuclear repulsion energy	79.198450

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at B1B95/cc-pVTZ

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)	Raman Act (Å⁴/u)	Dep P	Dep U
1	A_g	2271	2174	0.00	410.60	0.12	0.22
2	A_g	937	897	0.00	10.62	0.35	0.52
3	A_g	602	577	0.00	90.65	0.21	0.35
4	A_u	557	533	0.00	0.00	0.00	0.00
5	B_1u	2264	2167	63.59	0.00	0.00	0.00
6	B_1u	855	819	108.55	0.00	0.00	0.00
7	B_2g	158i	151i	0.00	23.43	0.75	0.86
8	B_2u	2301	2202	99.60	0.00	0.00	0.00
9	B_2u	346	331	18.07	0.00	0.00	0.00
10	B_3g	2291	2193	0.00	213.77	0.75	0.86
11	B_3g	591	566	0.00	4.23	0.75	0.86
12	B_3u	534	511	1.36	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6695.7 cm^-1
Scaled (by 0.9571) Zero Point Vibrational Energy (zpe) 6408.5 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at B1B95/cc-pVTZ

A	B	C
2.68748	0.21901	0.20251

See section I.F.4 to change rotational constant units

Geometric Data calculated at B1B95/cc-pVTZ

Point Group is D_2h

Cartesians (Å)

Atom	y (Å)	z (Å)
Si1	0.000	1.063
Si2	0.000	-1.063
H3	1.247	1.849
H4	-1.247	1.849
H5	1.247	-1.849
H6	-1.247	-1.849

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1253	1.4747	1.4747	3.1679	3.1679
Si2	2.1253		3.1679	3.1679	1.4747	1.4747
H3	1.4747	3.1679		2.4948	3.6986	4.4614
H4	1.4747	3.1679	2.4948		4.4614	3.6986
H5	3.1679	1.4747	3.6986	4.4614		2.4948
H6	3.1679	1.4747	4.4614	3.6986	2.4948

picture of Disilene state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	122.237	Si1	Si2	H6	122.237
Si2	Si1	H3	122.237	Si2	Si1	H4	122.237
H3	Si1	H4	115.526	H5	Si2	H6	115.526

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B1B95/cc-pVTZ Charges (e)

Number	Element	Mulliken
1	Si	-0.045
2	Si	-0.045
3	H	0.022
4	H	0.022
5	H	0.022
6	H	0.022

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.000	0.000
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-31.301	0.000	0.000
y	0.000	-28.991	0.000
z	0.000	0.000	-27.140

Traceless
	x	y	z
x	-3.236	0.000	0.000
y	0.000	0.230	0.000
z	0.000	0.000	3.006

Polar
3z²-r²	6.012
x²-y²	-2.310
xy	0.000
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	6.895	0.000	0.000
y	0.000	7.873	0.000
z	0.000	0.000	14.362

<r²> (average value of r²) Å²

<r²>	69.725
(<r²>)^1/2	8.350

Conformer 2 (C2H)

Jump to S1C1 S1C3

Energy calculated at B1B95/cc-pVTZ

	hartrees
Energy at 0K	-581.383845
Energy at 298.15K
HF Energy	-581.383845
Nuclear repulsion energy	78.815084

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at B1B95/cc-pVTZ

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)	Raman Act (Å⁴/u)	Dep P	Dep U
1	A_g	2254	2157	0.00	420.28	0.13	0.23
2	A_g	941	901	0.00	16.00	0.41	0.58
3	A_g	587	561	0.00	78.14	0.23	0.38
4	A_g	233	223	0.00	23.81	0.29	0.45
5	A_u	2282	2184	116.13	0.00	0.00	0.00
6	A_u	540	517	0.00	0.00	0.00	0.00
7	A_u	340	325	16.86	0.00	0.00	0.00
8	B_g	2272	2174	0.00	236.22	0.75	0.86
9	B_g	599	573	0.00	6.08	0.75	0.86
10	B_u	2248	2152	87.51	0.00	0.00	0.00
11	B_u	887	849	146.54	0.00	0.00	0.00
12	B_u	479	458	15.54	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6830.9 cm^-1
Scaled (by 0.9571) Zero Point Vibrational Energy (zpe) 6537.8 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at B1B95/cc-pVTZ

A	B	C
2.59562	0.21645	0.20139

See section I.F.4 to change rotational constant units

Geometric Data calculated at B1B95/cc-pVTZ

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.071	0.000
Si2	0.000	-1.071	0.000
H3	0.317	1.817	1.236
H4	0.317	1.817	-1.236
H5	-0.317	-1.817	1.236
H6	-0.317	-1.817	-1.236

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1418	1.4780	1.4780	3.1570	3.1570
Si2	2.1418		3.1570	3.1570	1.4780	1.4780
H3	1.4780	3.1570		2.4720	3.6883	4.4401
H4	1.4780	3.1570	2.4720		4.4401	3.6883
H5	3.1570	1.4780	3.6883	4.4401		2.4720
H6	3.1570	1.4780	4.4401	3.6883	2.4720

picture of Disilene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	120.302	Si1	Si2	H6	120.302
Si2	Si1	H3	120.302	Si2	Si1	H4	120.302
H3	Si1	H4	113.496	H5	Si2	H6	113.496

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B1B95/cc-pVTZ Charges (e)

Number	Element	Mulliken
1	Si	-0.033
2	Si	-0.033
3	H	0.016
4	H	0.016
5	H	0.016
6	H	0.016

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.000	0.000
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-31.193	-0.278	0.000
y	-0.278	-27.270	0.000
z	0.000	0.000	-29.180

Traceless
	x	y	z
x	-2.968	-0.278	0.000
y	-0.278	2.917	0.000
z	0.000	0.000	0.051

Polar
3z²-r²	0.103
x²-y²	-3.923
xy	-0.278
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	6.948	-0.320	0.000
y	-0.320	14.595	0.000
z	0.000	0.000	8.066

<r²> (average value of r²) Å²

<r²>	70.074
(<r²>)^1/2	8.371

Conformer 3 (C2V)

Jump to S1C1 S1C2

Energy calculated at B1B95/cc-pVTZ

	hartrees
Energy at 0K	-581.352405
Energy at 298.15K
HF Energy	-581.352405
Nuclear repulsion energy	73.560794

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at B1B95/cc-pVTZ

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)	Raman Act (Å⁴/u)	Dep P	Dep U
1	A₁	2111	2021	311.58	264.13	0.28	0.43
2	A₁	1637	1567	0.06	67.05	0.09	0.16
3	A₁	867	830	23.09	36.43	0.31	0.47
4	A₁	390	373	0.97	31.81	0.21	0.35
5	A₁	349	334	0.05	16.21	0.55	0.71
6	A₂	1434	1372	0.00	0.05	0.75	0.86
7	A₂	638	610	0.00	0.27	0.75	0.86
8	B₁	1326	1269	22.19	0.20	0.75	0.86
9	B₁	829	793	13.76	21.32	0.75	0.86
10	B₂	2085	1995	14.68	22.77	0.75	0.86
11	B₂	1413	1352	1034.01	12.53	0.75	0.86
12	B₂	721	690	82.71	10.44	0.75	0.86

Unscaled Zero Point Vibrational Energy (zpe) 6899.0 cm^-1
Scaled (by 0.9571) Zero Point Vibrational Energy (zpe) 6603.0 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at B1B95/cc-pVTZ

A	B	C
2.53870	0.16684	0.16310

See section I.F.4 to change rotational constant units

Geometric Data calculated at B1B95/cc-pVTZ

Point Group is C_2v

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.306	-0.090
Si2	0.000	-1.306	-0.090
H3	-1.036	0.000	-0.157
H4	1.036	0.000	-0.157
H5	0.000	1.298	1.422
H6	0.000	-1.298	1.422

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.6126	1.6683	1.6683	1.5125	3.0117
Si2	2.6126		1.6683	1.6683	3.0117	1.5125
H3	1.6683	1.6683		2.0712	2.2918	2.2918
H4	1.6683	1.6683	2.0712		2.2918	2.2918
H5	1.5125	3.0117	2.2918	2.2918		2.5961
H6	3.0117	1.5125	2.2918	2.2918	2.5961

picture of Disilene state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	30.146	Si1	Si2	H6	89.688
Si2	Si1	H3	38.464	Si2	Si1	H4	38.464
H3	Si1	H4	76.738	H5	Si2	H6	59.542

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B1B95/cc-pVTZ Charges (e)

Number	Element	Mulliken
1	Si	-0.001
2	Si	-0.001
3	H	0.005
4	H	0.005
5	H	-0.003
6	H	-0.003

Electric dipole moments
Electric dipole components in Debye
(What's a Debye? See section VII.A.3)

	x	y	z	Total
	0.000	0.000	0.421	0.421
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-27.095	0.000	0.000
y	0.000	-31.739	0.000
z	0.000	0.000	-33.067

Traceless
	x	y	z
x	5.308	0.000	0.000
y	0.000	-1.658	0.000
z	0.000	0.000	-3.650

Polar
3z²-r²	-7.301
x²-y²	4.644
xy	0.000
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	7.295	0.000	0.000
y	0.000	13.181	0.000
z	0.000	0.000	8.812

<r²> (average value of r²) Å²

<r²>	76.751
(<r²>)^1/2	8.761

All results from a given calculation for Si2H4 (Disilene)

using model chemistry: B1B95/cc-pVTZ

States and conformations

Conformer 1 (D2H)

Conformer 2 (C2H)

Conformer 3 (C2V)

All results from a given calculation for Si₂H₄ (Disilene)