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

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

Calculated Ionization Energy for Se2 (Selenium diatomic)

Experimental Ionization Energy is 8.6 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  
PM6  
composite G2 8.846
G3B3 8.972
G4 8.942
CBS-Q 9.072

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
hartree fock HF 7.224 9.394 8.805 9.609 8.918 8.918 8.978 8.960 8.960 8.826 8.931 8.965 8.910 8.904 8.993   8.907
density functional LSDA 7.588 -4.206 9.331 9.804 9.440 9.440 9.508 9.516 9.516 9.358   9.493 9.480   9.530    
SVWN   9.585         9.508       9.494            
BLYP 6.833 8.804 8.572 9.046 8.704   8.805     8.622   8.750 8.772        
B1B95 6.658 -3.332 9.057 9.729   9.255 8.415 9.207 9.207 9.148   9.203 8.968   9.041    
B3LYP 7.279 9.233 8.928 9.463 9.050 9.050 9.131 9.128 9.128 8.962 9.109 9.099 9.089 9.079 9.149 9.089 9.082
B3LYPultrafine                               9.090  
B3PW91 7.418 9.383 9.043 9.583 9.137 9.137 9.189 9.175 9.175 9.050   9.194 9.139        
mPW1PW91 7.455 9.422 9.061 9.619 9.154 9.154 9.209 9.191 9.191 9.068   9.210 9.159        
M06-2X     9.223   9.223                        
PBEPBE 7.066 9.057 8.783 9.272 8.894 8.894 8.970 8.959 8.959 8.814   8.941 8.929        
PBE1PBE         9.127                        
HSEh1PBE   8.370     9.077   9.135           9.085        
TPSSh         9.054   9.106     8.968     9.069        
wB97X-D     9.023   9.123       9.130       9.083     9.080  
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
Moller Plesset perturbation MP2   8.005 8.416 8.324 8.556 8.556 8.624 8.610 8.610 8.648 8.583 8.552     8.696    
MP2=FULL   8.000 8.410 8.304 8.557 8.557 8.624 8.639 8.639 8.649   8.546          
MP3=FULL         8.708   8.774                    
MP4   8.326     8.539       8.591       8.786        
B2PLYP         8.817               8.905        
Configuration interaction CID         8.746                        
CISD         8.737                        
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
Quadratic configuration interaction QCISD   8.443 8.513 8.722 8.656 8.656   8.722 8.722 8.785   8.656 8.920        
Coupled Cluster CCD   8.468 8.535 8.743 8.674 8.674   8.741 8.741 8.795   8.679          
CCSD         8.664                        
CCSD(T)                       8.560 8.841   8.737    
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

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 9.589   9.589   9.713 9.580
density functional B3LYP 9.533   9.533   9.640 9.533
Moller Plesset perturbation MP2 8.229   8.229   8.302 8.270
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.