	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: B3PW91/6-31+G**

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 B3PW91/6-31+G**

	hartrees
Energy at 0K	-581.228626
Energy at 298.15K
HF Energy	-581.228626
Nuclear repulsion energy	78.765274

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 B3PW91/6-31+G**

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	2275	2184	0.00
2	A_g	945	907	0.00
3	A_g	593	569	0.00
4	A_u	545	523	0.00
5	B_1u	2268	2177	79.50
6	B_1u	864	829	107.68
7	B_2g	228i	219i	0.00
8	B_2u	2305	2213	144.76
9	B_2u	357	343	16.64
10	B_3g	2295	2203	0.00
11	B_3g	600	576	0.00
12	B_3u	517	497	0.61

Unscaled Zero Point Vibrational Energy (zpe) 6666.9 cm^-1
Scaled (by 0.9601) Zero Point Vibrational Energy (zpe) 6400.9 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 B3PW91/6-31+G**

A	B	C
2.66029	0.21642	0.20013

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

Geometric Data calculated at B3PW91/6-31+G**

Point Group is D_2h

Cartesians (Å)

Atom	y (Å)	z (Å)
Si1	0.000	1.070
Si2	0.000	-1.070
H3	1.254	1.856
H4	-1.254	1.856
H5	1.254	-1.856
H6	-1.254	-1.856

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1392	1.4798	1.4798	3.1826	3.1826
Si2	2.1392		3.1826	3.1826	1.4798	1.4798
H3	1.4798	3.1826		2.5075	3.7114	4.4791
H4	1.4798	3.1826	2.5075		4.4791	3.7114
H5	3.1826	1.4798	3.7114	4.4791		2.5075
H6	3.1826	1.4798	4.4791	3.7114	2.5075

picture of Disilene state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	122.088	Si1	Si2	H6	122.088
Si2	Si1	H3	122.088	Si2	Si1	H4	122.088
H3	Si1	H4	115.824	H5	Si2	H6	115.824

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3PW91/6-31+G** Charges (e)

Number	Element	Mulliken
1	Si	0.095
2	Si	0.095
3	H	-0.048
4	H	-0.048
5	H	-0.048
6	H	-0.048

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	-31.716	0.000	0.000
y	0.000	-28.940	0.000
z	0.000	0.000	-27.536

Traceless
	x	y	z
x	-3.478	0.000	0.000
y	0.000	0.686	0.000
z	0.000	0.000	2.792

Polar
3z²-r²	5.584
x²-y²	-2.777
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	7.047	0.000	0.000
y	0.000	6.769	0.000
z	0.000	0.000	14.726

<r²> (average value of r²) Å²

<r²>	70.456
(<r²>)^1/2	8.394

Conformer 2 (C2H)

Jump to S1C1 S1C3

Energy calculated at B3PW91/6-31+G**

	hartrees
Energy at 0K	-581.229604
Energy at 298.15K
HF Energy	-581.229604
Nuclear repulsion energy	78.136798

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 B3PW91/6-31+G**

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	2247	2158	0.00
2	A_g	949	911	0.00
3	A_g	570	547	0.00
4	A_g	307	295	0.00
5	A_u	2276	2185	176.25
6	A_u	528	507	0.26
7	A_u	346	332	16.97
8	B_g	2265	2174	0.00
9	B_g	612	587	0.00
10	B_u	2242	2152	127.82
11	B_u	908	872	165.84
12	B_u	448	430	28.68

Unscaled Zero Point Vibrational Energy (zpe) 6848.2 cm^-1
Scaled (by 0.9601) Zero Point Vibrational Energy (zpe) 6575.0 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 B3PW91/6-31+G**

A	B	C
2.51950	0.21220	0.19824

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

Geometric Data calculated at B3PW91/6-31+G**

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.083	0.000
Si2	0.000	-1.083	0.000
H3	0.404	1.803	1.234
H4	0.404	1.803	-1.234
H5	-0.404	-1.803	1.234
H6	-0.404	-1.803	-1.234

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1667	1.4852	1.4852	3.1656	3.1656
Si2	2.1667		3.1656	3.1656	1.4852	1.4852
H3	1.4852	3.1656		2.4686	3.6965	4.4451
H4	1.4852	3.1656	2.4686		4.4451	3.6965
H5	3.1656	1.4852	3.6965	4.4451		2.4686
H6	3.1656	1.4852	4.4451	3.6965	2.4686

picture of Disilene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	119.004	Si1	Si2	H6	119.004
Si2	Si1	H3	119.004	Si2	Si1	H4	119.004
H3	Si1	H4	112.425	H5	Si2	H6	112.425

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3PW91/6-31+G** Charges (e)

Number	Element	Mulliken
1	Si	0.107
2	Si	0.107
3	H	-0.053
4	H	-0.053
5	H	-0.053
6	H	-0.053

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	-31.504	-0.287	0.000
y	-0.287	-27.692	0.000
z	0.000	0.000	-29.241

Traceless
	x	y	z
x	-3.037	-0.287	0.000
y	-0.287	2.680	0.000
z	0.000	0.000	0.357

Polar
3z²-r²	0.714
x²-y²	-3.812
xy	-0.287
xz	0.000
yz	0.000

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

	x	y	z
x	7.037	-0.623	0.000
y	-0.623	14.962	0.000
z	0.000	0.000	7.235

<r²> (average value of r²) Å²

<r²>	71.033
(<r²>)^1/2	8.428

Conformer 3 (C2V)

Jump to S1C1 S1C2

Energy calculated at B3PW91/6-31+G**

	hartrees
Energy at 0K	-581.190988
Energy at 298.15K
HF Energy	-581.190988
Nuclear repulsion energy	72.993755

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 B3PW91/6-31+G**

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A₁	2102	2018	425.93
2	A₁	1659	1593	0.03
3	A₁	889	853	38.73
4	A₁	408	392	1.25
5	A₁	379	364	0.61
6	A₂	1402	1346	0.00
7	A₂	636	610	0.00
8	B₁	1324	1272	43.71
9	B₁	842	808	13.05
10	B₂	2073	1990	12.86
11	B₂	1379	1324	1141.26
12	B₂	728	699	77.58

Unscaled Zero Point Vibrational Energy (zpe) 6910.0 cm^-1
Scaled (by 0.9601) Zero Point Vibrational Energy (zpe) 6634.3 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 B3PW91/6-31+G**

A	B	C
2.52508	0.16379	0.16008

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

Geometric Data calculated at B3PW91/6-31+G**

Point Group is C_2v

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.318	-0.089
Si2	0.000	-1.318	-0.089
H3	-1.031	0.000	-0.179
H4	1.031	0.000	-0.179
H5	0.000	1.328	1.430
H6	0.000	-1.328	1.430

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.6363	1.6762	1.6762	1.5195	3.0515
Si2	2.6363		1.6762	1.6762	3.0515	1.5195
H3	1.6762	1.6762		2.0630	2.3274	2.3274
H4	1.6762	1.6762	2.0630		2.3274	2.3274
H5	1.5195	3.0515	2.3274	2.3274		2.6563
H6	3.0515	1.5195	2.3274	2.3274	2.6563

picture of Disilene state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	29.864	Si1	Si2	H6	90.377
Si2	Si1	H3	38.149	Si2	Si1	H4	38.149
H3	Si1	H4	75.961	H5	Si2	H6	60.512

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3PW91/6-31+G** Charges (e)

Number	Element	Mulliken
1	Si	0.230
2	Si	0.230
3	H	-0.147
4	H	-0.147
5	H	-0.084
6	H	-0.084

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	0.802	0.802
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-27.168	0.000	0.000
y	0.000	-32.657	0.000
z	0.000	0.000	-33.455

Traceless
	x	y	z
x	5.888	0.000	0.000
y	0.000	-2.345	0.000
z	0.000	0.000	-3.543

Polar
3z²-r²	-7.085
x²-y²	5.489
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	6.305	0.000	0.000
y	0.000	13.225	0.000
z	0.000	0.000	8.220

<r²> (average value of r²) Å²

<r²>	78.106
(<r²>)^1/2	8.838

All results from a given calculation for Si2H4 (Disilene)

using model chemistry: B3PW91/6-31+G**

States and conformations

Conformer 1 (D2H)

Conformer 2 (C2H)

Conformer 3 (C2V)

All results from a given calculation for Si₂H₄ (Disilene)