	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: B3PW91/STO-3G

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 B3PW91/STO-3G

	hartrees
Energy at 0K	-574.502079
Energy at 298.15K
HF Energy	-574.502079
Nuclear repulsion energy	82.373987

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 B3PW91/STO-3G

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	2667	2361	0.00	174.28	0.11	0.19
2	A_g	1100	974	0.00	38.63	0.75	0.86
3	A_g	744	658	0.00	28.45	0.35	0.51
4	A_u	699	619	0.00	0.00	0.00	0.00
5	B_1u	2662	2356	0.00	0.00	0.00	0.00
6	B_1u	1005	889	164.93	0.00	0.00	0.00
7	B_2g	447i	396i	0.00	15.69	0.75	0.86
8	B_2u	2725	2411	28.55	0.00	0.00	0.00
9	B_2u	440	389	27.16	0.00	0.00	0.00
10	B_3g	2717	2405	0.00	123.44	0.75	0.86
11	B_3g	693	613	0.00	6.73	0.75	0.86
12	B_3u	540	478	27.29	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 7771.9 cm^-1
Scaled (by 0.885) Zero Point Vibrational Energy (zpe) 6878.1 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 B3PW91/STO-3G

A	B	C
2.85234	0.23903	0.22055

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

Geometric Data calculated at B3PW91/STO-3G

Point Group is D_2h

Cartesians (Å)

Atom	y (Å)	z (Å)
Si1	0.000	1.014
Si2	0.000	-1.014
H3	1.211	1.795
H4	-1.211	1.795
H5	1.211	-1.795
H6	-1.211	-1.795

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.0281	1.4407	1.4407	3.0587	3.0587
Si2	2.0281		3.0587	3.0587	1.4407	1.4407
H3	1.4407	3.0587		2.4216	3.5896	4.3301
H4	1.4407	3.0587	2.4216		4.3301	3.5896
H5	3.0587	1.4407	3.5896	4.3301		2.4216
H6	3.0587	1.4407	4.3301	3.5896	2.4216

picture of Disilene state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	122.815	Si1	Si2	H6	122.815
Si2	Si1	H3	122.815	Si2	Si1	H4	122.815
H3	Si1	H4	114.370	H5	Si2	H6	114.370

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3PW91/STO-3G Charges (e)

Number	Element	Mulliken
1	Si	0.213
2	Si	0.213
3	H	-0.107
4	H	-0.107
5	H	-0.107
6	H	-0.107

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	-23.985	0.000	0.000
y	0.000	-25.476	0.000
z	0.000	0.000	-25.530

Traceless
	x	y	z
x	1.518	0.000	0.000
y	0.000	-0.718	0.000
z	0.000	0.000	-0.799

Polar
3z²-r²	-1.599
x²-y²	1.491
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	1.084	0.000	0.000
y	0.000	2.999	0.000
z	0.000	0.000	6.671

<r²> (average value of r²) Å²

<r²>	63.155
(<r²>)^1/2	7.947

Conformer 2 (C2H)

Jump to S1C1 S1C3

Energy calculated at B3PW91/STO-3G

	hartrees
Energy at 0K	-574.511027
Energy at 298.15K
HF Energy	-574.511027
Nuclear repulsion energy	80.513323

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 B3PW91/STO-3G

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	2617	2316	0.00	201.44	0.11	0.20
2	A_g	1149	1017	0.00	42.43	0.73	0.84
3	A_g	708	627	0.00	12.28	0.65	0.79
4	A_g	535	474	0.00	27.65	0.16	0.27
5	A_u	2672	2365	68.87	0.00	0.00	0.00
6	A_u	638	564	0.13	0.00	0.00	0.00
7	A_u	412	365	19.90	0.00	0.00	0.00
8	B_g	2663	2357	0.00	141.49	0.75	0.86
9	B_g	737	652	0.00	6.66	0.75	0.86
10	B_u	2621	2320	33.78	0.00	0.00	0.00
11	B_u	1143	1011	276.52	0.00	0.00	0.00
12	B_u	472	417	38.29	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 8183.0 cm^-1
Scaled (by 0.885) Zero Point Vibrational Energy (zpe) 7242.0 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 B3PW91/STO-3G

A	B	C
2.51428	0.22572	0.21377

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

Geometric Data calculated at B3PW91/STO-3G

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.052	0.000
Si2	0.000	-1.052	0.000
H3	0.610	1.674	1.162
H4	0.610	1.674	-1.162
H5	-0.610	-1.674	1.162
H6	-0.610	-1.674	-1.162

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1033	1.4524	1.4524	3.0253	3.0253
Si2	2.1033		3.0253	3.0253	1.4524	1.4524
H3	1.4524	3.0253		2.3231	3.5641	4.2543
H4	1.4524	3.0253	2.3231		4.2543	3.5641
H5	3.0253	1.4524	3.5641	4.2543		2.3231
H6	3.0253	1.4524	4.2543	3.5641	2.3231

picture of Disilene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	115.383	Si1	Si2	H6	115.383
Si2	Si1	H3	115.383	Si2	Si1	H4	115.383
H3	Si1	H4	106.214	H5	Si2	H6	106.214

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3PW91/STO-3G Charges (e)

Number	Element	Mulliken
1	Si	0.245
2	Si	0.245
3	H	-0.122
4	H	-0.122
5	H	-0.122
6	H	-0.122

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	-24.437	-1.322	0.000
y	-1.322	-25.073	0.000
z	0.000	0.000	-25.940

Traceless
	x	y	z
x	1.070	-1.322	0.000
y	-1.322	0.115	0.000
z	0.000	0.000	-1.185

Polar
3z²-r²	-2.370
x²-y²	0.636
xy	-1.322
xz	0.000
yz	0.000

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

	x	y	z
x	1.730	-0.279	0.000
y	-0.279	7.309	0.000
z	0.000	0.000	3.007

<r²> (average value of r²) Å²

<r²>	64.774
(<r²>)^1/2	8.048

Conformer 3 (C2V)

Jump to S1C1 S1C2

Energy calculated at B3PW91/STO-3G

	hartrees
Energy at 0K	-574.448605
Energy at 298.15K
HF Energy	-574.448605
Nuclear repulsion energy	73.689831

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 B3PW91/STO-3G

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	2536	2244	238.47	110.73	0.32	0.48
2	A₁	1927	1706	0.00	23.29	0.26	0.41
3	A₁	1180	1044	53.38	11.61	0.35	0.52
4	A₁	574	508	0.04	7.48	0.37	0.54
5	A₁	461	408	0.36	16.21	0.28	0.44
6	A₂	1524	1349	0.00	6.32	0.75	0.86
7	A₂	768	680	0.00	2.36	0.75	0.86
8	B₁	1556	1377	27.78	2.58	0.75	0.86
9	B₁	1127	997	33.37	5.67	0.75	0.86
10	B₂	2519	2229	2.57	3.60	0.75	0.86
11	B₂	1515	1340	1309.68	1.50	0.75	0.86
12	B₂	896	793	18.40	10.23	0.75	0.86

Unscaled Zero Point Vibrational Energy (zpe) 8291.7 cm^-1
Scaled (by 0.885) Zero Point Vibrational Energy (zpe) 7338.2 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 B3PW91/STO-3G

A	B	C
2.65410	0.16519	0.16158

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

Geometric Data calculated at B3PW91/STO-3G

Point Group is C_2v

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.317	-0.086
Si2	0.000	-1.317	-0.086
H3	-1.005	0.000	-0.190
H4	1.005	0.000	-0.190
H5	0.000	1.226	1.395
H6	0.000	-1.226	1.395

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.6331	1.6597	1.6597	1.4838	2.9422
Si2	2.6331		1.6597	1.6597	2.9422	1.4838
H3	1.6597	1.6597		2.0105	2.2417	2.2417
H4	1.6597	1.6597	2.0105		2.2417	2.2417
H5	1.4838	2.9422	2.2417	2.2417		2.4515
H6	2.9422	1.4838	2.2417	2.2417	2.4515

picture of Disilene state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	30.223	Si1	Si2	H6	86.491
Si2	Si1	H3	37.510	Si2	Si1	H4	37.510
H3	Si1	H4	74.554	H5	Si2	H6	56.268

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3PW91/STO-3G Charges (e)

Number	Element	Mulliken
1	Si	0.339
2	Si	0.339
3	H	-0.171
4	H	-0.171
5	H	-0.168
6	H	-0.168

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	0.111	0.111
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-23.201	0.000	0.000
y	0.000	-26.281	0.000
z	0.000	0.000	-27.863

Traceless
	x	y	z
x	3.871	0.000	0.000
y	0.000	-0.749	0.000
z	0.000	0.000	-3.122

Polar
3z²-r²	-6.244
x²-y²	3.080
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	2.844	0.000	0.000
y	0.000	6.458	0.000
z	0.000	0.000	2.947

<r²> (average value of r²) Å²

<r²>	73.834
(<r²>)^1/2	8.593

All results from a given calculation for Si2H4 (Disilene)

using model chemistry: B3PW91/STO-3G

States and conformations

Conformer 1 (D2H)

Conformer 2 (C2H)

Conformer 3 (C2V)

All results from a given calculation for Si₂H₄ (Disilene)