National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
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XVEntropy data
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XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for Ca (Calcium atom)

Experimental Ionization Energy is 6.11316 ± 0.00002 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 6.190
G2MP2 6.208
G2 6.173
G3B3 6.196
G3MP2 6.265
G4 6.065

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-pVTZ
hartree fock HF 4.014 5.118 5.108 5.128 5.122 5.122 5.122 5.119 5.119 5.119 5.119  
density functional LSDA 5.937 6.133 6.615 6.670 6.638 6.638 6.638 6.648 6.648 6.635    
SVWN                     6.633  
BLYP 5.284 6.103 6.063 6.092 6.062 6.062 6.062 6.070 6.070 6.061    
B1B95     5.885 226.304     5.908 5.911 5.911      
B3LYP 5.352   6.148 6.179 6.151 6.151 6.150 6.156 6.156 6.148 6.146  
B3PW91 5.220 6.023 5.983 6.032 6.005 6.005 6.005 6.006 6.006 6.004    
mPW1PW91 5.168 6.012 5.973 6.011 5.983 5.983 5.983 5.983 5.983 5.983    
M06-2X     6.266                  
PBEPBE 5.298 6.113 6.068 6.111 6.079 6.079 6.078 6.083 6.083 6.077    
PBE1PBE         6.003              
TPSSh         5.978   5.978     5.979   5.964
wB97X-D     6.017   6.074       6.072     6.058
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-pVTZ
Moller Plesset perturbation MP2 4.441 5.499 5.595 5.511 5.659 5.659 5.660 5.779 5.779 5.796 5.520  
MP2=FULL 4.445 5.504 5.631 5.511 5.659 5.659 5.660 5.782 5.782 5.796    
MP3             5.812          
MP3=FULL         5.812   5.812          
MP4   5.782     5.871       5.955      
B2PLYP                       5.954
Configuration interaction CID   5.830     5.858              
CISD   5.831     5.865              
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-pVTZ
Quadratic configuration interaction QCISD   5.831   5.816 5.884 5.884 5.885 5.935 5.935 5.927    
QCISD(T)         5.897              
Coupled Cluster CCD   5.830   5.815 5.876 5.876 5.877 5.917 5.917 5.914    
CCSD         5.884              
CCSD(T)         5.897              
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-pVTZ

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 5.295   5.295   5.311 5.153
density functional B3LYP 6.109   6.109   6.439 6.208
Moller Plesset perturbation MP2 5.694   5.694   5.690 5.888
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.