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Calculated Ionization Energy for K (Potassium atom)

Experimental Ionization Energy is 4.34066 ± 0.00001 eV
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 G1 4.269
G2MP2 4.279
G2 4.271
G3B3 4.307
G3MP2 4.324
G4 4.317

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 Def2TZVPP cc-pVDZ
hartree fock HF 1.862 3.983 3.984 4.010 4.010 4.010 4.010 4.003 4.003 4.010   4.009 4.009  
ROHF   3.982 3.983 4.008 4.008 4.008 4.008 4.001 4.001          
density functional LSDA 3.463 4.824 4.834 4.887 4.917 4.917 4.917 4.915 4.915 4.917        
BLYP 2.871 4.382 4.383 4.406 4.432 4.432 4.433 4.426 4.426 4.433        
B1B95     4.218 4.260 4.288 4.266 4.266 4.255 4.255 4.271        
B3LYP 2.895 4.452 4.453 4.480 4.502 4.502 4.502 4.494 4.494 4.502   4.489 4.489  
B3LYPultrafine         4.502                  
B3PW91 2.736 4.318 4.320 4.364 4.373 4.373 4.373 4.365 4.365 4.377        
mPW1PW91 2.675 4.322 4.324 4.353 4.360 4.360 4.360 4.351 4.351 4.365        
M06-2X     4.137                      
PBEPBE 2.808 4.407 4.408 4.432 4.446 4.446 4.446 4.439 4.439 4.450     4.436  
PBE1PBE         4.377                  
TPSSh         4.240   4.240     4.246        
wB97X-D     4.038   4.130   4.129   4.122     4.117   4.129
B97D3   3.941     3.970   3.970   3.961   3.963      
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 Def2TZVPP cc-pVDZ
Moller Plesset perturbation MP2 1.862 3.983 3.984 4.015 4.124 4.124 4.126 4.234 4.234 4.157   4.009 4.009  
MP2=FULL 1.896 3.989 4.020 4.015 4.124 4.124 4.126 4.237 4.237 4.157        
MP3             4.140              
MP3=FULL         4.140   4.142              
MP4   3.983     4.146       4.243          
Configuration interaction CID   3.983 3.984 4.017 4.141     4.198            
CISD   3.983 3.984 4.017 4.144     4.204            
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 Def2TZVPP cc-pVDZ
Quadratic configuration interaction QCISD   3.983 3.984 4.017 4.147 4.147 4.149 4.237 4.237 4.161        
QCISD(T)         4.148                  
Coupled Cluster CCD   3.983 3.984 4.017 4.143 4.143 4.146 4.224 4.224 4.158        
CCSD         4.146                  
CCSD(T)         4.148                  
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 Def2TZVPP cc-pVDZ

Ionization Energies in eV
Methods with effective core potentials (select basis sets)
daug-cc-pVDZ daug-cc-pVTZ daug-cc-pVQZ Sadlej_pVTZ CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF                 3.985 3.996
density functional B3LYP                 4.445 4.497
Moller Plesset perturbation MP2                 3.990 4.030
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.