	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: PBEPBEultrafine/Def2TZVPP

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 PBEPBEultrafine/Def2TZVPP

	hartrees
Energy at 0K	-581.028241
Energy at 298.15K
HF Energy	-581.028241
Nuclear repulsion energy	78.495519

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 PBEPBEultrafine/Def2TZVPP

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	2193	2193	0.00	424.63	0.11	0.20
2	A_g	906	906	0.00	10.88	0.41	0.58
3	A_g	574	574	0.00	82.62	0.22	0.35
4	A_u	530	530	0.00	0.00	0.00	0.00
5	B_1u	2188	2188	49.78	0.00	0.00	0.00
6	B_1u	828	828	100.96	0.00	0.00	0.00
7	B_2g	233i	233i	0.00	18.34	0.75	0.86
8	B_2u	2226	2226	81.04	0.00	0.00	0.00
9	B_2u	335	335	14.69	0.00	0.00	0.00
10	B_3g	2216	2216	0.00	214.26	0.75	0.86
11	B_3g	575	575	0.00	5.37	0.75	0.86
12	B_3u	488	488	0.52	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6413.0 cm^-1
Scaled (by 1) Zero Point Vibrational Energy (zpe) 6413.0 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 PBEPBEultrafine/Def2TZVPP

A	B	C
2.63616	0.21513	0.19890

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

Geometric Data calculated at PBEPBEultrafine/Def2TZVPP

Point Group is D_2h

Cartesians (Å)

Atom	y (Å)	z (Å)
Si1	0.000	1.073
Si2	0.000	-1.073
H3	1.259	1.863
H4	-1.259	1.863
H5	1.259	-1.863
H6	-1.259	-1.863

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1450	1.4871	1.4871	3.1945	3.1945
Si2	2.1450		3.1945	3.1945	1.4871	1.4871
H3	1.4871	3.1945		2.5190	3.7265	4.4980
H4	1.4871	3.1945	2.5190		4.4980	3.7265
H5	3.1945	1.4871	3.7265	4.4980		2.5190
H6	3.1945	1.4871	4.4980	3.7265	2.5190

picture of Disilene state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	122.122	Si1	Si2	H6	122.122
Si2	Si1	H3	122.122	Si2	Si1	H4	122.122
H3	Si1	H4	115.756	H5	Si2	H6	115.756

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at PBEPBEultrafine/Def2TZVPP Charges (e)

Number	Element	Mulliken
1	Si	0.038
2	Si	0.038
3	H	-0.019
4	H	-0.019
5	H	-0.019
6	H	-0.019

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	-31.650	0.000	0.000
y	0.000	-29.020	0.000
z	0.000	0.000	-27.247

Traceless
	x	y	z
x	-3.517	0.000	0.000
y	0.000	0.429	0.000
z	0.000	0.000	3.088

Polar
3z²-r²	6.176
x²-y²	-2.630
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	6.843	0.000	0.000
y	0.000	8.126	0.000
z	0.000	0.000	14.778

<r²> (average value of r²) Å²

<r²>	70.745
(<r²>)^1/2	8.411

Conformer 2 (C2H)

Jump to S1C1 S1C3

Energy calculated at PBEPBEultrafine/Def2TZVPP

	hartrees
Energy at 0K	-581.029368
Energy at 298.15K
HF Energy	-581.029368
Nuclear repulsion energy	77.842296

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 PBEPBEultrafine/Def2TZVPP

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	2162	2162	0.00	441.78	0.12	0.22
2	A_g	909	909	0.00	19.80	0.49	0.66
3	A_g	549	549	0.00	63.35	0.26	0.42
4	A_g	311	311	0.00	19.74	0.10	0.18
5	A_u	2194	2194	108.04	0.00	0.00	0.00
6	A_u	507	507	0.00	0.00	0.00	0.00
7	A_u	325	325	12.91	0.00	0.00	0.00
8	B_g	2183	2183	0.00	247.85	0.75	0.86
9	B_g	587	587	0.00	8.51	0.75	0.86
10	B_u	2159	2159	88.03	0.00	0.00	0.00
11	B_u	876	876	152.54	0.00	0.00	0.00
12	B_u	410	410	20.44	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6585.3 cm^-1
Scaled (by 1) Zero Point Vibrational Energy (zpe) 6585.3 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 PBEPBEultrafine/Def2TZVPP

A	B	C
2.47881	0.21086	0.19709

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

Geometric Data calculated at PBEPBEultrafine/Def2TZVPP

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.087	0.000
Si2	0.000	-1.087	0.000
H3	0.425	1.803	1.239
H4	0.425	1.803	-1.239
H5	-0.425	-1.803	1.239
H6	-0.425	-1.803	-1.239

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1740	1.4932	1.4932	3.1732	3.1732
Si2	2.1740		3.1732	3.1732	1.4932	1.4932
H3	1.4932	3.1732		2.4790	3.7050	4.4578
H4	1.4932	3.1732	2.4790		4.4578	3.7050
H5	3.1732	1.4932	3.7050	4.4578		2.4790
H6	3.1732	1.4932	4.4578	3.7050	2.4790

picture of Disilene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	118.653	Si1	Si2	H6	118.653
Si2	Si1	H3	118.653	Si2	Si1	H4	118.653
H3	Si1	H4	112.211	H5	Si2	H6	112.211

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at PBEPBEultrafine/Def2TZVPP Charges (e)

Number	Element	Mulliken
1	Si	0.050
2	Si	0.050
3	H	-0.025
4	H	-0.025
5	H	-0.025
6	H	-0.025

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	-31.369	-0.291	0.000
y	-0.291	-27.543	0.000
z	0.000	0.000	-29.356

Traceless
	x	y	z
x	-2.920	-0.291	0.000
y	-0.291	2.820	0.000
z	0.000	0.000	0.100

Polar
3z²-r²	0.200
x²-y²	-3.826
xy	-0.291
xz	0.000
yz	0.000

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

	x	y	z
x	7.020	-0.266	0.000
y	-0.266	15.079	0.000
z	0.000	0.000	8.489

<r²> (average value of r²) Å²

<r²>	71.334
(<r²>)^1/2	8.446

Conformer 3 (C2V)

Jump to S1C1 S1C2

Energy calculated at PBEPBEultrafine/Def2TZVPP

	hartrees
Energy at 0K	-580.995059
Energy at 298.15K
HF Energy	-580.995059
Nuclear repulsion energy	72.787588

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 PBEPBEultrafine/Def2TZVPP

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	2024	2024	286.69	257.41	0.30	0.47
2	A₁	1582	1582	0.09	63.34	0.09	0.16
3	A₁	822	822	16.19	46.59	0.31	0.47
4	A₁	375	375	1.02	47.98	0.29	0.44
5	A₁	350	350	0.01	8.52	0.72	0.84
6	A₂	1394	1394	0.00	0.49	0.75	0.86
7	A₂	606	606	0.00	0.13	0.75	0.86
8	B₁	1275	1275	15.73	0.33	0.75	0.86
9	B₁	759	759	9.84	22.73	0.75	0.86
10	B₂	1998	1998	13.12	26.42	0.75	0.86
11	B₂	1324	1324	751.22	20.54	0.75	0.86
12	B₂	676	676	61.77	6.38	0.75	0.86

Unscaled Zero Point Vibrational Energy (zpe) 6591.9 cm^-1
Scaled (by 1) Zero Point Vibrational Energy (zpe) 6591.9 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 PBEPBEultrafine/Def2TZVPP

A	B	C
2.49560	0.16315	0.15942

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

Geometric Data calculated at PBEPBEultrafine/Def2TZVPP

Point Group is C_2v

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.321	-0.090
Si2	0.000	-1.321	-0.090
H3	-1.038	0.000	-0.183
H4	1.038	0.000	-0.183
H5	0.000	1.315	1.438
H6	0.000	-1.315	1.438

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.6424	1.6826	1.6826	1.5281	3.0469
Si2	2.6424		1.6826	1.6826	3.0469	1.5281
H3	1.6826	1.6826		2.0753	2.3313	2.3313
H4	1.6826	1.6826	2.0753		2.3313	2.3313
H5	1.5281	3.0469	2.3313	2.3313		2.6298
H6	3.0469	1.5281	2.3313	2.3313	2.6298

picture of Disilene state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	30.100	Si1	Si2	H6	89.763
Si2	Si1	H3	38.258	Si2	Si1	H4	38.258
H3	Si1	H4	76.153	H5	Si2	H6	59.663

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at PBEPBEultrafine/Def2TZVPP Charges (e)

Number	Element	Mulliken
1	Si	0.042
2	Si	0.042
3	H	-0.011
4	H	-0.011
5	H	-0.031
6	H	-0.031

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	0.380	0.380
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-27.258	0.000	0.000
y	0.000	-31.901	0.000
z	0.000	0.000	-33.136

Traceless
	x	y	z
x	5.260	0.000	0.000
y	0.000	-1.704	0.000
z	0.000	0.000	-3.557

Polar
3z²-r²	-7.114
x²-y²	4.643
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	7.399	0.000	0.000
y	0.000	14.124	0.000
z	0.000	0.000	9.131

<r²> (average value of r²) Å²

<r²>	78.133
(<r²>)^1/2	8.839

All results from a given calculation for Si2H4 (Disilene)

using model chemistry: PBEPBEultrafine/Def2TZVPP

States and conformations

Conformer 1 (D2H)

Conformer 2 (C2H)

Conformer 3 (C2V)

All results from a given calculation for Si₂H₄ (Disilene)