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XVII.C.1.

Calculated Ionization Energy for CH (Methylidyne)

Experimental Ionization Energy is 10.64 ± 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  
composite G4 10.633
CBS-Q 10.591

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 aug-cc-pVQZ cc-pV(T+d)Z
hartree fock HF 8.535 10.153 10.153 10.068 10.061 10.058 10.146 10.140 10.143 10.104   10.123 10.175 10.186 10.180 10.188 10.191 10.175
density functional LSDA 9.572 11.371 11.371 11.308 11.287 11.293 11.448 11.428 11.435 11.324   11.377 11.474   11.479     11.474
BLYP 9.145 10.728 10.728 10.687 10.665 10.669 10.846 10.802 10.808 10.707   10.764 10.857         10.857
B1B95 9.147 10.693 10.693 10.631 10.600 10.605 10.737 10.701 10.707 10.636   10.680 10.737   10.760     10.737
B3LYP 9.332 10.905 10.905 10.851 10.827 10.830 10.978 10.946 10.951 10.867 10.990 10.916 10.992 11.009 11.013 11.016 11.020 10.992
B3LYPultrafine         10.827                          
B3PW91 9.391 10.985 10.985 10.897 10.884 10.887 11.005 10.977 10.982 10.919   10.958 11.020         11.020
mPW1PW91 9.380 10.948 10.963 10.876 10.850 10.853 10.974 10.942 10.962 10.900   10.925 10.989         10.989
M06-2X         10.516                          
PBEPBE 9.256 10.885 10.885 10.827 10.816 10.819 10.974 10.929 10.934 10.852   10.905 10.983         10.983
TPSSh             10.911                      
Moller Plesset perturbation MP2 8.267 10.163 10.163 10.109 10.263 10.296 10.411 10.420 10.466 10.478 10.451 10.425 10.622 10.671 10.542 10.659 10.688 10.622
MP2=FULL   10.161     10.268 10.301 10.417 10.425 10.471     10.426 10.636 10.689 10.544     10.636
MP3         10.217                          
MP3=FULL         10.223   10.374                      
MP4   10.023     10.176                          
B2PLYP                         10.786          
Configuration interaction CID         10.114     10.275                    
CISD         10.116                          
Quadratic configuration interaction QCISD   9.962     10.112 10.142 10.254 10.280 10.321     10.285 10.496         10.496
QCISD(T)         10.120             10.296 10.526         10.526
Coupled Cluster CCD   9.969     10.110 10.141 10.251 10.274       10.282 10.486         10.486
CCSD(T)         10.118             10.295 10.525     10.566   10.525

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 10.223 10.201 10.145 10.120 10.186 10.176
density functional B3LYP 10.991 10.958 10.923 10.892 11.009 10.981
Moller Plesset perturbation MP2 10.221 10.376 10.175 10.329 10.233 10.226
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.