	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
	Home All data for one species Geometry Experimental Experimental Geometries Same bond/angle many molecules Internal Coordinates by type Bond angles Calculated Calculated geometry Rotational constant Moments of inertia Products of moments of inertia BSE Bond lengths Show me a calculated geometry Comparisons Bonds, angles Rotational Constants Products of moments of inertia Point group Bad Calculations Bad moment of inertia Tutorials and Explanations Angle formulas Vibrations Experimental Vibrational frequencies Calculated Frequencies Scale factors Reactions Entropies Ions List Ions Energy Calculated Ionization Energy Compare Ionzation energy Electron Affinity Calculated Electron affinity Compare Electron affinity Proton Affinity Calculated Proton affinity Compare Proton affinity Ionization changes point group Experimental One molecule all properties One property a few molecules Enthalpy of formation Entropy Integrated Heat Capacity Heat Capacity Rotational Constants Vibrational Frequencies Dipole moment Ionization Energy Polarizability Quadrupole Point Groups Geometry Experimental Geometries Internal Coordinates by type Bond angles Rotational Constants Point Groups Diatomic bond lengths Vibrations Vibrational frequencies Diatomic Triatomics Energy Atomization Energy Internal Rotation Electrostatics Dipole Quadrupole Polarizability Reference Data Reference states Spin Splittings Molecules with good enthalpy Enthalpy at 0 Kelvin Calculated Energy Optimized Energy Energy 298K Minimum conformation Hydrogen bonds H bond with counterpoise Reaction Reaction Energy 0K Reaction Energy 298K Internal Rotation Barriers to internal rotation Rotational barrier and dipole Rotational Barrier 2 molecules Orbital HOMO LUMO gap HOMO Orbital Energies Nuclear repulsion energy Correlation Full vs Frozen core energies Partial correlation energies Ion Calculated Ionization Energy Vertical ionization Energy Calculated Electron affinity Calculated Proton affinity Atom charge differences Excited State Singlet triplet gap Electronic state Transition state Basis Set Extrapolation BSE energy BSE Bond lengths Geometry Calculated geometry AIM bond orders One type of bond Rotation Rotational constant Products of moments of inertia Moments of inertia Inertial defects Second moments Point group State symmetry <r2> Sorted by r2 Z-matrix Bad Calculations Bad moment of inertia Bad Calculated Bond Lengths Bad point group Worst molecules Vibrations Frequencies Animated vibrations Anharmonic Zero point energy (ZPE) Scale Factors Scale factors Scale factor uncertainty Calculate a scale factor Why scale vibrations Set scaling factors Bad Calculations Bad Vib. HF vs MP2 Bad vib. Calc. vs exp. Big anharmonicity Electrostatics Charges Mulliken CHELP Aim ESP Dipole Dipole Dipole angle Dipole calculation types Quadrupole Polarizability Spin Spin density Entropy and Heat Capacity Entropy Reaction entropy Heat Capacity Reaction Reaction Energy 0K Reaction Energy 298K Isodesmic reactions Transition State Transition state Transition state frequencies Transition state geometries IRC Lookup by property By frequency Comparisons Geometry Bonds, angles Bond, angle, or dihedral DFT grid size on point group DFT grid on bond length Core correlation - bond length Same bond/angle many molecules Isoelectronic diatomics Isoelectronic triatomic angles Average bond lengths Rotation Rotational Constants Products of moments of inertia Point group Vibrations Vibrations 2 calculations Frequency differences One frequency Zero point energy Intensity Intensity for one mode Vibrational intensities Reduced mass comparison Anharmonic Triatomic Scale factors Energy Reaction Reaction Energy 0K Reaction Energy 298K Atomization 0K Atomization 298K Single point vs optimized DFT grid size on energy Semiempirical enthalpy Internal rotation Similar molecules Conformation Sets of isomers Sets of tautomers Isomers Entropy Entropy Heat capacity Entropy of several molecules Integrated heat capacity Reaction entropy Electrostatics Dipole Polarizability Several molecules Quadrupole Ion Compare Ionzation energy Koopman ionization energy Koopman IE for a few molecules Compare Electron affinity Compare Proton affinity Protonation Site Resources Info on Results Calculations Done Method and basis set List molecules One molecule Multiple conformers, states Multiple conformers, states Basis functions used I/O files Input/output files MOL file Z-matrix wfn files Glossary Conversion Forms B to I, I to B Angle formulas Integrated heat Capacity Calculating Enthalpy Links NIST Links NIST webbook bibliographic data CCCBDB Experimental data External links Basis Set Exchange Computational Chemistry List Thermochemistry in Gaussian Minnesota Database Collection Benchmark Energy and Geometry Point Groups Thermochemistry Thermochemistry Molecules with good enthalpy A → B + C Reference states Tutorials Vibrations Why scale vibrations Zero-point energies Entropy Methyl rotor entropy Entropy and conformations Energy Getting enthalpy of formation Vertical vs adiabatic IE Thermo from calculations Electrostatics Dipole parts by point group Quadrupoles Geometry Angle formulas Cost Cost Comparison Timings Comparison Bad Calculations Geometry Bad moment of inertia Bad Calculated Bond Lengths Bad point group Worst molecules Vibrations Bad vib. Calc. vs exp. Bad Vib. HF vs MP2 Bad scale factors Low excited states Oddities NaCN Is not linear FAQ Help Units Choose Units Energy Bond length Rotational Constant Moment of Inertia Dipole and Quadrupole Polarizability Explanations Hartree cm-1 Debye Credits Just show me Show me a calculated geometry Summary Using older interface Limit Basis sets Method options List Recent molecules Choose a few Molecules Number of atoms By heavy atoms Diatomics InChI Deuterated Dimers Geometry Point group Point group count Bonds types Isodesmic reactions Bad point group Multiple conformers, states Vibrations Big anharmonicity Energy Enthalpy at 0 Kelvin Similar molecules Similar Isomers Cis/trans Tautomers Multiple conformers, states Ions, Dipoles, etc. List Ions Ionization changes point group Dipole Quadrupole Polarizability Proton Affinities Index of CCCBDB Feedback Error form Wants
You are here: Calculated > Energy > Optimized > Energy

All results from a given calculation for Si₂H₄ (Disilene)

using model chemistry: B3LYP/CEP-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 B3LYP/CEP-31G

	hartrees
Energy at 0K	-10.034567
Energy at 298.15K
HF Energy	-10.034567
Nuclear repulsion energy	13.070467

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-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	2176	2107	0.00	479.77	0.33	0.49
2	A_g	892	863	0.00	42.95	0.56	0.72
3	A_g	572	554	0.00	86.08	0.29	0.44
4	A_u	543	525	0.00	0.00	0.00	0.00
5	B_1u	2167	2099	65.18	0.00	0.00	0.00
6	B_1u	802	776	107.20	0.00	0.00	0.00
7	B_2g	269i	261i	0.00	97.12	0.75	0.86
8	B_2u	2223	2153	229.99	0.00	0.00	0.00
9	B_2u	357	346	10.47	0.00	0.00	0.00
10	B_3g	2206	2137	0.00	265.42	0.75	0.86
11	B_3g	583	565	0.00	6.59	0.75	0.86
12	B_3u	493	478	2.02	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6372.3 cm^-1
Scaled (by 0.9684) Zero Point Vibrational Energy (zpe) 6171.0 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 B3LYP/CEP-31G

A	B	C
2.58805	0.20795	0.19249

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

Geometric Data calculated at B3LYP/CEP-31G

Point Group is D_2h

Cartesians (Å)

Atom	y (Å)	z (Å)
Si1	0.000	1.092
Si2	0.000	-1.092
H3	1.271	1.886
H4	-1.271	1.886
H5	1.271	-1.886
H6	-1.271	-1.886

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.1840	1.4987	1.4987	3.2380	3.2380
Si2	2.1840		3.2380	3.2380	1.4987	1.4987
H3	1.4987	3.2380		2.5423	3.7720	4.5487
H4	1.4987	3.2380	2.5423		4.5487	3.7720
H5	3.2380	1.4987	3.7720	4.5487		2.5423
H6	3.2380	1.4987	4.5487	3.7720	2.5423

picture of Disilene state 1 conformation 1

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	121.990	Si1	Si2	H6	121.990
Si2	Si1	H3	121.990	Si2	Si1	H4	121.990
H3	Si1	H4	116.020	H5	Si2	H6	116.020

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3LYP/CEP-31G Charges (e)

Number	Element	Mulliken
1	Si	0.046
2	Si	0.046
3	H	-0.023
4	H	-0.023
5	H	-0.023
6	H	-0.023

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	-29.893	0.000	0.000
y	0.000	-26.684	0.000
z	0.000	0.000	-25.567

Traceless
	x	y	z
x	-3.768	0.000	0.000
y	0.000	1.046	0.000
z	0.000	0.000	2.722

Polar
3z²-r²	5.444
x²-y²	-3.209
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	3.993	0.000	0.000
y	0.000	5.301	0.000
z	0.000	0.000	14.495

<r²> (average value of r²) Å²

<r²>	47.333
(<r²>)^1/2	6.880

Conformer 2 (C2H)

Jump to S1C1 S1C3

Energy calculated at B3LYP/CEP-31G

	hartrees
Energy at 0K	-10.036390
Energy at 298.15K
HF Energy	-10.036390
Nuclear repulsion energy	12.986071

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-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	2131	2064	0.00	466.07	0.24	0.39
2	A_g	907	878	0.00	62.97	0.59	0.74
3	A_g	548	531	0.00	62.63	0.41	0.58
4	A_g	350	339	0.00	40.70	0.29	0.45
5	A_u	2180	2111	302.32	0.00	0.00	0.00
6	A_u	523	506	0.31	0.00	0.00	0.00
7	A_u	342	331	10.41	0.00	0.00	0.00
8	B_g	2161	2093	0.00	363.24	0.75	0.86
9	B_g	597	578	0.00	13.27	0.75	0.86
10	B_u	2127	2060	134.73	0.00	0.00	0.00
11	B_u	877	850	195.19	0.00	0.00	0.00
12	B_u	427	414	40.82	0.00	0.00	0.00

Unscaled Zero Point Vibrational Energy (zpe) 6585.2 cm^-1
Scaled (by 0.9684) Zero Point Vibrational Energy (zpe) 6377.1 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 B3LYP/CEP-31G

A	B	C
2.42176	0.20174	0.18934

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

Geometric Data calculated at B3LYP/CEP-31G

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.112	0.000
Si2	0.000	-1.112	0.000
H3	0.470	1.827	1.242
H4	0.470	1.827	-1.242
H5	-0.470	-1.827	1.242
H6	-0.470	-1.827	-1.242

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.2243	1.5082	1.5082	3.2256	3.2256
Si2	2.2243		3.2256	3.2256	1.5082	1.5082
H3	1.5082	3.2256		2.4836	3.7739	4.5178
H4	1.5082	3.2256	2.4836		4.5178	3.7739
H5	3.2256	1.5082	3.7739	4.5178		2.4836
H6	3.2256	1.5082	4.5178	3.7739	2.4836

picture of Disilene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	118.312	Si1	Si2	H6	118.312
Si2	Si1	H3	118.312	Si2	Si1	H4	118.312
H3	Si1	H4	110.846	H5	Si2	H6	110.846

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3LYP/CEP-31G Charges (e)

Number	Element	Mulliken
1	Si	0.076
2	Si	0.076
3	H	-0.038
4	H	-0.038
5	H	-0.038
6	H	-0.038

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	-29.545	0.356	0.000
y	0.356	-25.823	0.000
z	0.000	0.000	-27.162

Traceless
	x	y	z
x	-3.052	0.356	0.000
y	0.356	2.530	0.000
z	0.000	0.000	0.522

Polar
3z²-r²	1.045
x²-y²	-3.722
xy	0.356
xz	0.000
yz	0.000

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

	x	y	z
x	4.043	-1.052	0.000
y	-1.052	14.726	0.000
z	0.000	0.000	5.850

<r²> (average value of r²) Å²

<r²>	47.488
(<r²>)^1/2	6.891

Conformer 3 (C2V)

Jump to S1C1 S1C2

Energy calculated at B3LYP/CEP-31G

	hartrees
Energy at 0K	-9.995783
Energy at 298.15K
HF Energy	-9.995783
Nuclear repulsion energy	13.196263

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-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	1955	1893	674.26	422.24	0.43	0.60
2	A₁	1515	1467	1.49	72.06	0.17	0.28
3	A₁	902	874	51.27	138.40	0.44	0.61
4	A₁	428	415	2.27	36.90	0.33	0.50
5	A₁	364	353	0.16	24.66	0.31	0.47
6	A₂	1125	1089	0.00	0.03	0.75	0.86
7	A₂	615	595	0.00	0.36	0.75	0.86
8	B₁	1126	1091	115.04	0.39	0.75	0.86
9	B₁	854	827	26.79	34.34	0.75	0.86
10	B₂	1923	1862	5.59	3.41	0.75	0.86
11	B₂	1189	1151	1427.21	23.74	0.75	0.86
12	B₂	710	687	39.41	21.16	0.75	0.86

Unscaled Zero Point Vibrational Energy (zpe) 6352.4 cm^-1
Scaled (by 0.9684) Zero Point Vibrational Energy (zpe) 6151.6 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-31G

A	B	C
2.41704	0.14418	0.14105

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

Geometric Data calculated at B3LYP/CEP-31G

Point Group is C_2v

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
Si1	0.000	1.407	-0.093
Si2	0.000	-1.407	-0.093
H3	-1.042	0.000	-0.173
H4	1.042	0.000	-0.173
H5	0.000	1.392	1.470
H6	0.000	-1.392	1.470

Atom - Atom Distances (Å)

	Si1	Si2	H3	H4	H5	H6
Si1		2.8147	1.7528	1.7528	1.5629	3.2065
Si2	2.8147		1.7528	1.7528	3.2065	1.5629
H3	1.7528	1.7528		2.0835	2.3925	2.3925
H4	1.7528	1.7528	2.0835		2.3925	2.3925
H5	1.5629	3.2065	2.3925	2.3925		2.7850
H6	3.2065	1.5629	2.3925	2.3925	2.7850

picture of Disilene state 1 conformation 3

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
Si1	Si2	H5	29.169	Si1	Si2	H6	89.455
Si2	Si1	H3	36.591	Si2	Si1	H4	36.591
H3	Si1	H4	72.931	H5	Si2	H6	60.287

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at B3LYP/CEP-31G Charges (e)

Number	Element	Mulliken
1	Si	0.291
2	Si	0.291
3	H	-0.193
4	H	-0.193
5	H	-0.098
6	H	-0.098

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	1.357	1.357
CHELPG
AIM
ESP

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-26.073	0.000	0.000
y	0.000	-30.315	0.000
z	0.000	0.000	-32.058

Traceless
	x	y	z
x	5.113	0.000	0.000
y	0.000	-1.249	0.000
z	0.000	0.000	-3.865

Polar
3z²-r²	-7.729
x²-y²	4.242
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	5.744	0.000	0.000
y	0.000	14.584	0.000
z	0.000	0.000	6.726

<r²> (average value of r²) Å²

<r²>	44.759
(<r²>)^1/2	6.690

All results from a given calculation for Si2H4 (Disilene)

using model chemistry: B3LYP/CEP-31G

States and conformations

Conformer 1 (D2H)

Conformer 2 (C2H)

Conformer 3 (C2V)

All results from a given calculation for Si₂H₄ (Disilene)