National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 22May 2022
NIST Standard Reference Database 101
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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for CP (Carbon monophosphide)

Experimental Ionization Energy is 10.5 ± 0.5 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  
composite CBS-Q 10.992
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) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
hartree fock HF 6.116 10.032   9.975 9.686 9.686 9.729 9.723 9.723 9.582   9.693 9.682 9.620 9.668 9.620 9.618
density functional LSDA 9.828 8.819 11.608 11.595 11.507 11.507 11.586 11.640 11.640 11.468     11.515 11.578 11.551    
BLYP 8.127 10.730 10.664 10.659 10.578 10.578 10.682 10.717 10.717 10.543     10.583 10.654      
B1B95 8.346   10.812 10.808 10.671 10.714 10.781 10.806 10.806 10.663     10.716 10.684 10.690    
B3LYP 7.171 10.922 10.841 10.847 10.749 10.749 10.834 10.868 10.868 10.703   10.833 10.752 10.798 10.795 10.805  
B3LYPultrafine         10.749                     10.805  
B3PW91 7.189   10.908   10.794 10.794 10.853 10.888 10.888 10.739     10.800 10.811      
mPW1PW91 7.751 10.943 10.871 10.869 10.736 10.736 10.798 10.829 10.852 10.701     10.737 10.746      
M06-2X     10.792   10.706           10.756            
PBEPBE 8.343 10.946 10.868 10.861 10.772 10.772 10.853 10.882 10.882 10.725     10.772 10.812      
PBE1PBE         10.753                        
HSEh1PBE   12.467     10.817   10.880             10.832      
TPSSh         10.731   10.790     10.676       10.748      
wB97X-D     10.859   10.732   10.790   10.827     10.779 10.790 10.731   10.733  
B97D3   10.837     10.646   10.721   10.755   10.704 10.715   10.677   10.684 10.682
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
Moller Plesset perturbation MP2 7.086 10.096 10.189 10.036 10.794 10.220 10.291 10.885 10.364 11.038   10.329 10.316 10.535 10.403 10.571  
MP2=FULL   10.093     10.225 10.225 10.294 10.369 10.369       10.320        
MP3         10.133                        
MP3=FULL         10.275   10.330                    
MP4         10.215                 10.582      
B2PLYP         10.654                 10.793      
B2PLYP=FULLultrafine         10.656               10.691 10.799   10.820  
Configuration interaction CID         10.044     10.158                  
CISD         10.113                        
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
Quadratic configuration interaction QCISD   10.338     10.365 10.365 10.431 10.482 10.482       10.359 10.664      
Coupled Cluster CCD         10.113     10.238         10.177        
CCSD(T)                           10.758      
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
Ionization Energies in eV
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 10.093 9.709 10.005 9.664 10.131 10.027     9.611
density functional B3LYP 10.880 10.711 10.775 10.648 10.971 10.935     10.800
PBEPBE                 10.814
Moller Plesset perturbation MP2 10.068 10.254 10.043 10.275 10.144 10.118     11.109
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.