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Calculated Ionization Energy for NaK (Sodium Potassium)

Experimental Ionization Energy is 4.41636 ± 0.00017 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 PM6  
composite G2 4.420
G3 4.470
G3B3 4.472
G4 4.374
CBS-Q 4.199

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 -0.069 3.445 3.419 3.469 3.463 3.463 3.463 3.466 3.466 3.445 3.472
density functional LSDA 2.437 5.034 5.034 5.102 5.100   5.099 5.099 5.099 5.090 5.089
SVWN   5.034     5.100 5.100 5.099 5.099 5.099 5.090  
BLYP 1.701 4.549 4.538 4.543 4.546 4.546 4.547 4.542 4.542 4.535 4.534
B1B95 1.366 4.223 4.220         3.919 3.919 4.290 4.296
B3LYP 1.675 4.590 4.577 4.596 4.595 4.595 4.595 4.586 4.586 4.579 4.584
B3LYPultrafine         4.595            
B3PW91 1.482 4.341 4.324 4.376 4.370 4.370 4.369 4.360 4.360 4.351 4.359
mPW1PW91 1.414 4.377 4.358 4.379 4.373 4.373 4.372 4.362 4.362 4.352 4.361
M06-2X 1.458 4.641 4.609 4.704 4.698 4.698 4.698 4.690   4.685 4.697
PBEPBE 1.680 4.543 4.531 4.555 4.551 4.551 4.551 4.545 4.545 4.531 4.539
HSEh1PBE 1.485 4.428 4.413 4.446 4.439 4.439   4.431 4.431 4.418 4.430
TPSSh         4.390   4.389     4.367  
wB97X-D     4.180   4.280   4.279   4.282   4.260
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP
Moller Plesset perturbation MP2 0.306   3.847 3.836 3.964 3.964 3.965 4.041 4.041 4.063  
MP2=FULL 0.368 3.813 3.883 3.840 3.978 3.978 3.980 4.072 4.072 4.107 3.860
MP3         4.095            
MP3=FULL         4.109   4.110        
MP4   4.001     4.151       4.214    
Configuration interaction CID   4.037 4.072 4.066 4.127     3.962      
CISD   4.045 4.076 4.074 4.133     3.967      
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP
Quadratic configuration interaction QCISD   4.045 4.076 4.076 4.178 4.178 4.179 4.221 4.221 4.246 4.062
QCISD(T)         4.190           4.062
Coupled Cluster CCD   4.037 4.072 4.067 4.170 4.170 4.171 4.208 4.208 4.237 4.053
CCSD         4.177            
CCSD(T)         4.190           4.062
CCSD(T)=FULL         4.203           4.098
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP

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 3.386   3.432   3.406 3.487
density functional B3LYP 4.186   4.208   4.432 4.611
Moller Plesset perturbation MP2         3.738 3.862
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.