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XVII.C.1.

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 PM6  
composite G1 4.269
G2MP2 4.279
G2 4.271
G3MP2 4.324
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
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
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
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  
PBEPBE 2.808 4.407 4.408 4.432 4.446 4.446 4.446 4.439 4.439 4.450  
Moller Plesset perturbation MP2FC 1.862 3.983 3.984 4.015 4.124 4.124 4.126 4.234 4.234 4.157 4.009
MP2FU 1.896 3.989 4.020 4.015 4.124 4.124 4.126 4.237 4.237 4.157  
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      
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            
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         3.985 3.996
density functional B3LYP         4.445 4.497
Moller Plesset perturbation MP2FC         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.