	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: HF/6-31G

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 HF/6-31G

	hartrees
Energy at 0K	-580.009155
Energy at 298.15K
HF Energy	-580.009155
Nuclear repulsion energy	78.432123

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 HF/6-31G

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	2330	2104	0.00	425.94	0.22	0.36
2	A_g	986	891	0.00	28.05	0.53	0.69
3	A_g	622	561	0.00	143.01	0.28	0.43
4	A_u	586	529	0.00	0.00	0.00	0.00
5	B_1u	2318	2093	131.16	0.00	0.00	0.00
6	B_1u	895	808	106.73	0.00	0.00	0.00
7	B_2g	173i	156i	0.00	137.59	0.75	0.86
8	B_2u	2356	2127	266.21	0.00	0.00	0.00
9	B_2u	396	357	29.23	0.00	0.00	0.00
10	B_3g	2345	2117	0.00	237.82	0.75	0.86
11	B_3g	624	564	0.00	7.88	0.75	0.86
12	B_3u	589	532	5.92	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6936.8 cm^-1
Scaled (by 0.9029) Zero Point Vibrational Energy (zpe) 6263.3 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 HF/6-31G

A	B	C
2.64714	0.21416	0.19813

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

Geometric Data calculated at HF/6-31G

Point Group is D_2h

Cartesians (Å)

Atom	y (Å)	z (Å)
Si1	0.000	1.076
Si2	0.000	-1.076
H3	1.257	1.859
H4	-1.257	1.859
H5	1.257	-1.859
H6	-1.257	-1.859

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1520	1.4807	1.4807	3.1927	3.1927
Si2	2.1520		3.1927	3.1927	1.4807	1.4807
H3	1.4807	3.1927		2.5137	3.7177	4.4878
H4	1.4807	3.1927	2.5137		4.4878	3.7177
H5	3.1927	1.4807	3.7177	4.4878		2.5137
H6	3.1927	1.4807	4.4878	3.7177	2.5137

picture of Disilene state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	121.917	Si1	Si2	H6	121.917
Si2	Si1	H3	121.917	Si2	Si1	H4	121.917
H3	Si1	H4	116.166	H5	Si2	H6	116.166

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at HF/6-31G Charges (e)

Number	Element	Mulliken
1	Si	0.275
2	Si	0.275
3	H	-0.138
4	H	-0.138
5	H	-0.138
6	H	-0.138

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	-32.857	0.000	0.000
y	0.000	-30.699	0.000
z	0.000	0.000	-29.588

Traceless
	x	y	z
x	-2.714	0.000	0.000
y	0.000	0.523	0.000
z	0.000	0.000	2.191

Polar
3z²-r²	4.381
x²-y²	-2.158
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	5.270	0.000	0.000
y	0.000	6.072	0.000
z	0.000	0.000	15.492

<r²> (average value of r²) Å²

<r²>	71.951
(<r²>)^1/2	8.482

Conformer 2 (C2H)

Jump to S1C1 S1C3

Energy calculated at HF/6-31G

	hartrees
Energy at 0K	-580.009452
Energy at 298.15K
HF Energy	-580.009452
Nuclear repulsion energy	78.011412

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 HF/6-31G

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	2313	2088	0.00	425.00	0.20	0.33
2	A_g	991	895	0.00	44.28	0.49	0.66
3	A_g	608	549	0.00	119.65	0.33	0.50
4	A_g	234	211	0.00	112.59	0.52	0.68
5	A_u	2337	2110	292.67	0.00	0.00	0.00
6	A_u	586	529	0.35	0.00	0.33	0.50
7	A_u	386	349	31.01	0.00	0.00	0.00
8	B_g	2325	2099	0.00	270.65	0.75	0.86
9	B_g	633	571	0.00	9.22	0.75	0.86
10	B_u	2302	2079	169.48	0.00	0.00	0.00
11	B_u	924	834	168.39	0.00	0.00	0.00
12	B_u	550	497	41.36	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 7094.7 cm^-1
Scaled (by 0.9029) Zero Point Vibrational Energy (zpe) 6405.8 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 HF/6-31G

A	B	C
2.58066	0.21124	0.19658

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

Geometric Data calculated at HF/6-31G

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.085	0.000
Si2	0.000	-1.085	0.000
H3	0.294	1.838	1.245
H4	0.294	1.838	-1.245
H5	-0.294	-1.838	1.245
H6	-0.294	-1.838	-1.245

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1694	1.4842	1.4842	3.1902	3.1902
Si2	2.1694		3.1902	3.1902	1.4842	1.4842
H3	1.4842	3.1902		2.4890	3.7227	4.4782
H4	1.4842	3.1902	2.4890		4.4782	3.7227
H5	3.1902	1.4842	3.7227	4.4782		2.4890
H6	3.1902	1.4842	4.4782	3.7227	2.4890

picture of Disilene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	120.501	Si1	Si2	H6	120.501
Si2	Si1	H3	120.501	Si2	Si1	H4	120.501
H3	Si1	H4	113.970	H5	Si2	H6	113.970

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at HF/6-31G Charges (e)

Number	Element	Mulliken
1	Si	0.287
2	Si	0.287
3	H	-0.144
4	H	-0.144
5	H	-0.144
6	H	-0.144

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	-32.838	-0.307	0.000
y	-0.307	-29.506	0.000
z	0.000	0.000	-30.874

Traceless
	x	y	z
x	-2.648	-0.307	0.000
y	-0.307	2.350	0.000
z	0.000	0.000	0.298

Polar
3z²-r²	0.596
x²-y²	-3.332
xy	-0.307
xz	0.000
yz	0.000

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

	x	y	z
x	5.353	-1.008	0.000
y	-1.008	15.713	0.000
z	0.000	0.000	6.396

<r²> (average value of r²) Å²

<r²>	72.406
(<r²>)^1/2	8.509

Conformer 3 (C2V)

Jump to S1C1 S1C2

Energy calculated at HF/6-31G

	hartrees
Energy at 0K	-579.965561
Energy at 298.15K
HF Energy	-579.965561
Nuclear repulsion energy	69.725896

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 HF/6-31G

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	2105	1900	678.62	383.36	0.33	0.50
2	A₁	1578	1425	0.13	84.69	0.17	0.29
3	A₁	1031	931	103.62	123.06	0.42	0.59
4	A₁	444	401	0.13	12.19	0.35	0.52
5	A₁	372	336	1.32	41.36	0.30	0.46
6	A₂	929	839	0.00	2.89	0.75	0.86
7	A₂	656	592	0.00	3.24	0.75	0.86
8	B₁	1138	1028	230.88	0.85	0.75	0.86
9	B₁	989	893	20.76	34.23	0.75	0.86
10	B₂	2076	1875	6.59	11.61	0.75	0.86
11	B₂	1300	1174	2941.76	4.25	0.75	0.86
12	B₂	811	732	127.29	35.79	0.75	0.86

Unscaled Zero Point Vibrational Energy (zpe) 6713.8 cm^-1
Scaled (by 0.9029) Zero Point Vibrational Energy (zpe) 6061.9 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 HF/6-31G

A	B	C
2.50912	0.14560	0.14264

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

Geometric Data calculated at HF/6-31G

Point Group is C_2v

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.398	-0.095
Si2	0.000	-1.398	-0.095
H3	-1.034	0.000	-0.108
H4	1.034	0.000	-0.108
H5	0.000	1.455	1.435
H6	0.000	-1.455	1.435

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.7959	1.7392	1.7392	1.5308	3.2375
Si2	2.7959		1.7392	1.7392	3.2375	1.5308
H3	1.7392	1.7392		2.0690	2.3595	2.3595
H4	1.7392	1.7392	2.0690		2.3595	2.3595
H5	1.5308	3.2375	2.3595	2.3595		2.9105
H6	3.2375	1.5308	2.3595	2.3595	2.9105

picture of Disilene state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	28.198	Si1	Si2	H6	92.145
Si2	Si1	H3	36.503	Si2	Si1	H4	36.503
H3	Si1	H4	73.000	H5	Si2	H6	63.947

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at HF/6-31G Charges (e)

Number	Element	Mulliken
1	Si	0.580
2	Si	0.580
3	H	-0.379
4	H	-0.379
5	H	-0.201
6	H	-0.201

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	1.085	1.085
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-29.373	0.000	0.000
y	0.000	-32.514	0.000
z	0.000	0.000	-35.794

Traceless
	x	y	z
x	4.781	0.000	0.000
y	0.000	0.069	0.000
z	0.000	0.000	-4.850

Polar
3z²-r²	-9.700
x²-y²	3.142
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	5.984	0.000	0.000
y	0.000	13.384	0.000
z	0.000	0.000	7.446

<r²> (average value of r²) Å²

<r²>	85.826
(<r²>)^1/2	9.264

All results from a given calculation for Si2H4 (Disilene)

using model chemistry: HF/6-31G

States and conformations

Conformer 1 (D2H)

Conformer 2 (C2H)

Conformer 3 (C2V)

All results from a given calculation for Si₂H₄ (Disilene)