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Calculated Ionization Energy for Ar2 (Argon dimer)

Experimental Ionization Energy is 14.501 ± 0.025 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 14.504
G3 14.444
G3B3 14.518
G4 14.446
CBS-Q 14.371

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 12.274 14.291 14.153 14.378 14.185 14.185 14.190 14.192 14.192 13.974 14.155 14.164 13.986 13.928 14.091 13.949 13.921
density functional LSDA 11.953 14.073 14.073 14.210 14.114 14.114 14.213 14.217 14.217 13.952 14.187 14.074 14.074   14.119 14.045  
SVWN   14.139     14.114 14.114 14.213 14.217 14.217 13.952   14.074 14.074   14.119 14.045  
BLYP 11.343 13.427 13.384 13.512 13.446 13.446 13.606     13.347 13.546 13.407 13.480        
B1B95 12.178 13.977 13.977 14.113 14.016 14.016 14.082 14.073 14.073 13.873 14.045 13.991 13.937   14.010 13.920  
B3LYP 11.944 13.977 13.923 14.065 13.976 13.976 14.086 14.072 14.072 13.849 14.040   13.950 13.928 14.016 13.947 13.930
B3LYPultrafine   13.973     13.975 13.975 14.084       14.041            
B3PW91 12.162 14.097 14.038       14.132 14.131 14.131 13.931 14.105 14.055 13.996     13.973  
mPW1PW91 12.190 14.122 14.054 14.196 14.094 14.094 14.153 14.148 14.148 13.941 14.117 14.072 14.000   14.076 13.980  
M06-2X 12.356 14.350 14.274 14.433 14.317 14.317 14.372 14.371 14.371 14.148 14.344 14.259 14.216   14.264 14.185  
PBEPBE 11.565 13.594 13.540 13.668 13.593 13.593 13.705 13.681 13.681 13.477 13.650 13.564 13.564   13.641 13.570  
PBEPBEultrafine   13.589     13.589 13.589 13.701 13.681     13.649 13.557 13.563   13.635 13.568  
PBE1PBE 12.093 13.996 13.996 14.144 14.041 14.041 14.101 14.091 14.091 13.887 14.060 14.017 13.942   14.022 13.925  
HSEh1PBE 12.074 14.040 13.973 14.115 14.013 14.013 14.076 14.071 14.071 13.864 14.039 13.988 13.925   13.997 13.906  
TPSSh     13.826 13.955 13.868 13.868 13.930 13.937     13.906 13.844 13.801   13.858 13.788  
wB97X-D 12.266 14.254 14.185 14.325 14.216 14.216 14.259 14.259 14.259 14.058 14.229 14.192 14.112 14.074 14.181 14.081 14.074
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   14.275 14.281 14.367 14.323 14.323 14.336 14.339 14.339 14.395 14.383 14.355 14.429 14.476 14.458 14.425 14.484
MP2=FULL   14.269 14.273 14.360 14.315 14.315 14.329 14.328 14.328 14.389 14.372 14.351 14.415 14.466 14.447 14.402 14.466
MP3         14.275   14.287       14.341 14.313 14.406        
MP3=FULL   14.278 14.231 14.357 14.265 14.265 14.278 14.279 14.279 14.360 14.328 14.306 14.387   14.401 14.368  
MP4   14.277     14.226       14.244   14.285 14.260 14.353   14.360 14.349  
MP4=FULL   14.270     14.216       14.230     14.253 14.335   14.347 14.321  
B2PLYP   14.118 14.068 14.213 14.118 14.118 14.186 14.178 14.178 14.047 14.170 14.105 14.114   14.179 14.110  
B2PLYP=FULL   14.117 14.065 14.211 14.115 14.115 14.184 14.175 14.175 14.045 14.167 14.104 14.110   14.176 14.104  
B2PLYP=FULLultrafine   14.139 14.056 14.232 14.104 14.104 14.170 14.164 14.165 13.943 14.129 14.073 14.007   14.087 13.987  
Configuration interaction CID   14.291 14.240 14.366 14.270     14.289                  
CISD   14.278 14.222 14.353 14.252     14.274                  
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   14.276 14.220 14.352 14.252 14.252 14.265 14.273 14.273 14.335 14.316 14.288 14.375   14.376 14.359  
QCISD(T)         14.215     14.232     14.273 14.248 14.337   14.344 14.330  
QCISD(T)=FULL         14.205   14.221         14.241 14.320 14.398 14.331 14.304 14.393
QCISD(TQ)         14.210   14.224         14.243 14.333   14.338 14.325  
QCISD(TQ)=FULL         14.200   14.215         14.237 14.316   14.325    
Coupled Cluster CCD   14.291 14.246 14.367 14.278 14.278 14.290 14.296 14.296 14.372 14.343 14.316 14.410   14.409 14.396  
CCSD         14.253         14.338 14.318 14.290 14.377 14.448 14.379 14.362 14.450
CCSD=FULL         14.244         14.329 14.306 14.284 14.361 14.435 14.366 14.337 14.429
CCSD(T)         14.215 14.215   14.232     14.274 14.249 14.339 14.414 14.344 14.332 14.418
CCSD(T)=FULL         14.205           14.261 14.242 14.321 14.400 14.331 14.306 14.395
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 14.540   14.442   14.460 14.378
density functional B3LYP 14.200   14.117   14.055 14.065
wB97X-D 14.437   14.356   14.398 14.325
Moller Plesset perturbation MP2 14.506   14.431   14.386 14.367
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.