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Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for Mg2 (Magnesium diatomic)

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 2.580
G3 6.506
G3B3 6.513
G4 6.515
CBS-Q 2.455

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 cc-pV(T+d)Z
hartree fock HF 0.329 1.176 1.179 1.072 1.039 1.039 1.076 5.444 5.444 1.074 5.684 5.459 5.437 5.434 5.451 5.437 5.434  
density functional LSDA 0.764 6.735 6.735 6.813 6.785 6.785 6.782 6.774 6.774 6.783   6.808 6.772   6.806 6.773   6.772
SVWN   6.774     6.785   6.782       6.809              
BLYP 0.114 6.258 6.173 6.276 6.233 6.233 6.231 6.221 6.221 6.231   6.260 6.224          
B1B95 -0.089 4.892 6.064 6.207 6.158 6.177   6.173 6.173 6.172   6.192 6.150   6.173 6.150   6.150
B3LYP 0.178 6.382 6.283 6.401 6.356 6.356 6.353 6.344 6.344 6.352 6.449 6.380 6.347 6.346 6.378 6.347 6.346  
B3LYPultrafine         6.356                     6.347    
B3PW91 0.071 6.219 6.160 6.258 6.224 6.224 6.222 6.206 6.206 6.218   6.239 6.209          
mPW1PW91 1.450 6.153 6.121 6.215 6.155 6.155 6.153 6.138 6.163 6.174   6.194 6.166         6.166
M06-2X     6.232   6.232                          
PBEPBE 0.065 6.248 6.204 6.267 6.233 6.233 6.231 6.216 6.216 6.232   6.253 6.218         6.218
PBE1PBE         6.192                          
HSEh1PBE   6.211     6.195               6.181          
TPSSh         6.107   6.104     6.099     6.087          
wB97X-D     6.023   6.273       6.271       6.258     6.258    
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 cc-pV(T+d)Z
Moller Plesset perturbation MP2 -0.716 1.729 5.997 1.636 1.955 1.935 6.098 6.105 6.105 2.157 6.063 6.096 6.135 6.154 6.104 6.144 6.159 6.135
MP2=FULL -0.732 1.733 6.000 6.109 6.102 6.102 1.979 6.134 6.134 6.117   6.095 6.136 6.215     6.216  
MP3         6.303                          
MP3=FULL         6.302   6.304                      
MP4   6.475     2.345       6.353       6.340          
B2PLYP         6.234               6.239          
Configuration interaction CID   6.432 6.170 6.463 1.893     6.282                    
CISD   6.361 6.085 6.388 6.195     6.194                    
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 cc-pV(T+d)Z
Quadratic configuration interaction QCISD   1.904 6.190 6.502 2.062 6.302 6.300 6.300 6.300 6.284   6.304 6.277         6.277
QCISD(T)         6.295             6.297 6.280   6.295 6.284    
Coupled Cluster CCD   6.542 6.275 6.576 2.101 6.391 6.388 6.390 6.390 6.376   6.393 6.371   6.387 6.373    
CCSD         2.054                          
CCSD(T)                       6.299 6.283   6.298 6.287   6.283
CCSD(T)=FULL         6.289                          
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 cc-pV(T+d)Z

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 5.637 5.537 5.559 5.461 5.601 5.990
density functional B3LYP 6.332 6.278 6.253 6.207 6.304 6.701
Moller Plesset perturbation MP2 6.198 6.176 6.135 6.121 6.197 6.565
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.