return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Calculated > Energy > Optimized > Energy

All results from a given calculation for C2 (Carbon diatomic)

using model chemistry: MP2/STO-3G

19 10 17 12 22

States and conformations

State Conformation minimum conformation conformer description state description
1 1 yes D*H 1Σg+
2 1 yes D*H 3Πu

State 1 (1Σg+)

Jump to S2C1
Energy calculated at MP2/STO-3G
 hartrees
Energy at 0K-74.666797
Energy at 298.15K-74.663769
HF Energy-74.419102
Nuclear repulsion energy14.948191
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 MP2/STO-3G
Mode Number Symmetry Frequency
(cm-1)
Scaled Frequency
(cm-1)
IR Intensities
(km mol-1)
Raman Act
4/u)
Dep P Dep U
1 Σg 1987 1732 0.00      

Unscaled Zero Point Vibrational Energy (zpe) 993.4 cm-1
Scaled (by 0.8719) Zero Point Vibrational Energy (zpe) 866.1 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 MP2/STO-3G
B
1.72988

See section I.F.4 to change rotational constant units
Geometric Data calculated at MP2/STO-3G

Point Group is D∞h

Cartesians (Å)
Atom x (Å) y (Å) z (Å)
C1 0.000 0.000 0.637
C2 0.000 0.000 -0.637

Atom - Atom Distances (Å)
  C1 C2
C11.2744
C21.2744

picture of Carbon diatomic state 1 conformation 1
More geometry information
Electronic energy levels
Charges, Dipole, Quadrupole and Polarizability

State 2 (3Πu)

Jump to S1C1
Energy calculated at MP2/STO-3G
 hartrees
Energy at 0K-74.632730
Energy at 298.15K-74.629698
HF Energy-74.494549
Nuclear repulsion energy14.112157
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 MP2/STO-3G
Mode Number Symmetry Frequency
(cm-1)
Scaled Frequency
(cm-1)
IR Intensities
(km mol-1)
Raman Act
4/u)
Dep P Dep U
1 Σg 1683 1467 0.00      

Unscaled Zero Point Vibrational Energy (zpe) 841.3 cm-1
Scaled (by 0.8719) Zero Point Vibrational Energy (zpe) 733.5 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 MP2/STO-3G
B
1.54179

See section I.F.4 to change rotational constant units
Geometric Data calculated at MP2/STO-3G

Point Group is D∞h

Cartesians (Å)
Atom x (Å) y (Å) z (Å)
C1 0.000 0.000 0.675
C2 0.000 0.000 -0.675

Atom - Atom Distances (Å)
  C1 C2
C11.3499
C21.3499

picture of Carbon diatomic state 2 conformation 1
More geometry information
Electronic energy levels
Charges, Dipole, Quadrupole and Polarizability