	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: B3LYP/CEP-121G

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 B3LYP/CEP-121G

	hartrees
Energy at 0K	-10.039517
Energy at 298.15K
HF Energy	-10.039517
Nuclear repulsion energy	13.064965

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 B3LYP/CEP-121G

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	2189	2134	0.00	553.39	0.21	0.34
2	A_g	892	869	0.00	26.52	0.62	0.77
3	A_g	569	554	0.00	96.42	0.24	0.39
4	A_u	540	526	0.00	0.00	0.00	0.00
5	B_1u	2182	2126	60.21	0.00	0.00	0.00
6	B_1u	802	782	107.14	0.00	0.00	0.00
7	B_2g	288i	281i	0.00	49.24	0.75	0.86
8	B_2u	2234	2177	177.62	0.00	0.00	0.00
9	B_2u	354	345	17.62	0.00	0.00	0.00
10	B_3g	2221	2164	0.00	300.86	0.75	0.86
11	B_3g	580	565	0.00	7.04	0.75	0.86
12	B_3u	493	480	0.44	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6383.6 cm^-1
Scaled (by 0.9745) Zero Point Vibrational Energy (zpe) 6220.9 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 B3LYP/CEP-121G

A	B	C
2.58432	0.20778	0.19231

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

Geometric Data calculated at B3LYP/CEP-121G

Point Group is D_2h

Cartesians (Å)

Atom	y (Å)	z (Å)
Si1	0.000	1.093
Si2	0.000	-1.093
H3	1.272	1.886
H4	-1.272	1.886
H5	1.272	-1.886
H6	-1.272	-1.886

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1851	1.4993	1.4993	3.2390	3.2390
Si2	2.1851		3.2390	3.2390	1.4993	1.4993
H3	1.4993	3.2390		2.5441	3.7725	4.5502
H4	1.4993	3.2390	2.5441		4.5502	3.7725
H5	3.2390	1.4993	3.7725	4.5502		2.5441
H6	3.2390	1.4993	4.5502	3.7725	2.5441

picture of Disilene state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	121.962	Si1	Si2	H6	121.962
Si2	Si1	H3	121.962	Si2	Si1	H4	121.962
H3	Si1	H4	116.076	H5	Si2	H6	116.076

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3LYP/CEP-121G Charges (e)

Number	Element	Mulliken
1	Si	0.101
2	Si	0.101
3	H	-0.051
4	H	-0.051
5	H	-0.051
6	H	-0.051

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	-29.889	0.000	0.000
y	0.000	-27.106	0.000
z	0.000	0.000	-25.849

Traceless
	x	y	z
x	-3.411	0.000	0.000
y	0.000	0.763	0.000
z	0.000	0.000	2.648

Polar
3z²-r²	5.296
x²-y²	-2.783
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	6.060	0.000	0.000
y	0.000	6.688	0.000
z	0.000	0.000	14.923

<r²> (average value of r²) Å²

<r²>	47.501
(<r²>)^1/2	6.892

Conformer 2 (C2H)

Jump to S1C1 S1C3

Energy calculated at B3LYP/CEP-121G

	hartrees
Energy at 0K	-10.041851
Energy at 298.15K
HF Energy	-10.041851
Nuclear repulsion energy	12.970294

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 B3LYP/CEP-121G

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	2140	2085	0.00	551.11	0.18	0.31
2	A_g	910	886	0.00	61.58	0.55	0.71
3	A_g	546	532	0.00	64.29	0.36	0.53
4	A_g	369	359	0.00	31.31	0.22	0.36
5	A_u	2185	2129	236.76	0.00	0.00	0.00
6	A_u	518	505	0.00	0.00	0.00	0.00
7	A_u	343	334	18.24	0.00	0.00	0.00
8	B_g	2169	2114	0.00	387.45	0.75	0.86
9	B_g	597	582	0.00	15.14	0.75	0.86
10	B_u	2136	2082	142.62	0.00	0.00	0.00
11	B_u	883	860	191.32	0.00	0.00	0.00
12	B_u	418	407	38.91	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6605.8 cm^-1
Scaled (by 0.9745) Zero Point Vibrational Energy (zpe) 6437.4 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 B3LYP/CEP-121G

A	B	C
2.39878	0.20081	0.18872

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

Geometric Data calculated at B3LYP/CEP-121G

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.115	0.000
Si2	0.000	-1.115	0.000
H3	0.494	1.820	1.241
H4	0.494	1.820	-1.241
H5	-0.494	-1.820	1.241
H6	-0.494	-1.820	-1.241

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.2307	1.5098	1.5098	3.2249	3.2249
Si2	2.2307		3.2249	3.2249	1.5098	1.5098
H3	1.5098	3.2249		2.4810	3.7720	4.5148
H4	1.5098	3.2249	2.4810		4.5148	3.7720
H5	3.2249	1.5098	3.7720	4.5148		2.4810
H6	3.2249	1.5098	4.5148	3.7720	2.4810

picture of Disilene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	117.826	Si1	Si2	H6	117.826
Si2	Si1	H3	117.826	Si2	Si1	H4	117.826
H3	Si1	H4	110.492	H5	Si2	H6	110.492

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3LYP/CEP-121G Charges (e)

Number	Element	Mulliken
1	Si	0.143
2	Si	0.143
3	H	-0.072
4	H	-0.072
5	H	-0.072
6	H	-0.072

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	-29.551	-0.188	0.000
y	-0.188	-26.121	0.000
z	0.000	0.000	-27.629

Traceless
	x	y	z
x	-2.675	-0.188	0.000
y	-0.188	2.469	0.000
z	0.000	0.000	0.206

Polar
3z²-r²	0.413
x²-y²	-3.429
xy	-0.188
xz	0.000
yz	0.000

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

	x	y	z
x	6.123	-0.753	0.000
y	-0.753	15.187	0.000
z	0.000	0.000	7.812

<r²> (average value of r²) Å²

<r²>	47.679
(<r²>)^1/2	6.905

Conformer 3 (C2V)

Jump to S1C1 S1C2

Energy calculated at B3LYP/CEP-121G

	hartrees
Energy at 0K	-10.002523
Energy at 298.15K
HF Energy	-10.002523
Nuclear repulsion energy	13.248521

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 B3LYP/CEP-121G

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	1962	1912	595.15	407.60	0.40	0.57
2	A₁	1533	1494	0.27	85.36	0.17	0.28
3	A₁	916	893	36.53	186.10	0.40	0.57
4	A₁	430	419	0.63	29.68	0.50	0.67
5	A₁	369	359	1.01	30.63	0.22	0.36
6	A₂	1157	1127	0.00	3.00	0.75	0.86
7	A₂	621	606	0.00	0.66	0.75	0.86
8	B₁	1129	1100	98.42	0.44	0.75	0.86
9	B₁	869	847	21.15	65.58	0.75	0.86
10	B₂	1934	1885	10.51	23.06	0.75	0.86
11	B₂	1220	1189	1468.90	18.24	0.75	0.86
12	B₂	720	702	45.52	37.88	0.75	0.86

Unscaled Zero Point Vibrational Energy (zpe) 6430.3 cm^-1
Scaled (by 0.9745) Zero Point Vibrational Energy (zpe) 6266.3 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 B3LYP/CEP-121G

A	B	C
2.43556	0.14591	0.14269

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

Geometric Data calculated at B3LYP/CEP-121G

Point Group is C_2v

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.398	-0.093
Si2	0.000	-1.398	-0.093
H3	-1.035	0.000	-0.164
H4	1.035	0.000	-0.164
H5	0.000	1.418	1.467
H6	0.000	-1.418	1.467

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.7956	1.7405	1.7405	1.5599	3.2186
Si2	2.7956		1.7405	1.7405	3.2186	1.5599
H3	1.7405	1.7405		2.0692	2.3954	2.3954
H4	1.7405	1.7405	2.0692		2.3954	2.3954
H5	1.5599	3.2186	2.3954	2.3954		2.8351
H6	3.2186	1.5599	2.3954	2.3954	2.8351

picture of Disilene state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	28.988	Si1	Si2	H6	90.726
Si2	Si1	H3	36.571	Si2	Si1	H4	36.571
H3	Si1	H4	72.945	H5	Si2	H6	61.738

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3LYP/CEP-121G Charges (e)

Number	Element	Mulliken
1	Si	0.233
2	Si	0.233
3	H	-0.138
4	H	-0.138
5	H	-0.095
6	H	-0.095

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	0.773	0.773
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-25.756	0.000	0.000
y	0.000	-30.139	0.000
z	0.000	0.000	-32.214

Traceless
	x	y	z
x	5.421	0.000	0.000
y	0.000	-1.154	0.000
z	0.000	0.000	-4.267

Polar
3z²-r²	-8.534
x²-y²	4.383
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	6.289	0.000	0.000
y	0.000	14.526	0.000
z	0.000	0.000	8.523

<r²> (average value of r²) Å²

<r²>	44.560
(<r²>)^1/2	6.675

All results from a given calculation for Si2H4 (Disilene)

using model chemistry: B3LYP/CEP-121G

States and conformations

Conformer 1 (D2H)

Conformer 2 (C2H)

Conformer 3 (C2V)

All results from a given calculation for Si₂H₄ (Disilene)