National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for CH3CN (Acetonitrile)

Experimental Ionization Energy is 12.2 ± 0.01 eV
Please note! These calculated ionizataion energies have the vibrational zero-point energy (zpe) included, but the zpe has NOT been scaled. Click on an entry for more details, including the ionization energy with a scaled zpe.
Original data displayed. Press to display differences.
Differences displayed. Press to display original data.

Ionization Energies in eV
Methods with predefined basis sets
semi-empirical PM3  
PM6  
composite G4 12.043

Ionization Energies in eV
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ
hartree fock HF 9.772 10.961 10.961 12.509 12.463 10.663 12.425 10.749 10.731 12.357 12.448 12.341 12.351 12.341 12.601 10.683
density functional LSDA 10.550 11.876 11.876 12.767 12.685 12.678 12.831 11.945 12.876 11.731   11.768     11.882  
SVWN   11.876         11.898       11.960          
BLYP 9.762 11.001 11.001 11.013 11.288 10.902 11.083 11.098 11.080 11.914   11.896 11.094      
B1B95 10.928 12.507 12.507 13.201 12.221 12.264 12.419 12.721 12.697 13.086   11.615 11.664   11.643 11.683
B3LYP 10.009 11.809 11.809 11.194 12.889 11.100 11.240 11.263 11.242 13.936 11.293 12.842 11.260   11.210 11.278
B3LYPultrafine         12.352                     11.804
B3PW91 10.068 12.503 12.503 11.847 12.521 12.521 11.805 12.654 11.823 12.659   11.691 12.761      
mPW1PW91 10.066 11.859 11.891 11.841 12.951 12.978 11.150 11.789 11.801 11.635   12.809 18.756      
M06-2X     11.968   11.940                      
PBEPBE 9.952 11.204 11.204 11.184 12.034 11.065 12.185 11.235 11.214 11.045   12.016 12.249      
PBE1PBE         14.474                      
HSEh1PBE   12.707     11.654   11.238           11.109      
TPSSh         11.569   11.626     11.477     11.649      
wB97X-D     11.913   11.732       11.848       11.807     11.835
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ
Moller Plesset perturbation MP2 11.548 12.370 12.370 15.370 12.228 12.345 14.918 12.346 12.475 15.040 14.844 14.839     15.643  
MP2=FULL   12.371     14.749 12.350 14.914 12.465 12.484 15.007   14.842        
MP3             11.741                  
MP3=FULL         11.699   11.892                  
B2PLYP         11.093                      
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ

Ionization Energies in eV
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 10.849 12.587 10.858 12.655 12.499 10.911
density functional B3LYP 12.077 11.865 12.167 11.963 12.680 11.266
Moller Plesset perturbation MP2 12.683 15.087 12.729 15.370 15.590 12.766
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.