National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 22May 2022
NIST Standard Reference Database 101
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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for CH3CHCH3 (Isopropyl radical)

Experimental Ionization Energy is 7.37 ± 0.02 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
composite G2 7.394
G3 7.463
G3B3 7.480
G4 7.506
CBS-Q 7.458

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) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ daug-cc-pVTZ
hartree fock HF 5.963 7.079 7.079 6.989 6.949 6.914 6.960 6.973 6.937 6.857 6.909 6.946 6.906 6.902 6.905 6.896 6.901 6.905 7.545
density functional LSDA 6.157 7.449 7.449 7.450 7.433 7.421 7.577 7.601 7.582 7.398 7.601 7.602 7.485 7.577   7.590 7.593    
BLYP 5.934 6.976 6.976 6.973 6.953 6.940 7.116 7.127 7.112 6.922 7.142 7.143 7.014 7.113   7.137 7.135    
B1B95 6.094 7.175 7.175 7.148 7.108 7.374 7.196 7.470 7.186 7.045 7.182 7.195 7.107 7.164   7.170 7.175    
B3LYP   7.293 7.293 7.271 7.249 7.230 7.366 7.384 7.362 7.201 7.374 7.384 7.281 7.353 7.367 7.366 7.366 7.372  
B3LYPultrafine   7.293     7.249 7.231 7.367 7.385     7.374 7.385 7.282 7.354   7.366 7.366    
B3PW91   7.378 7.378 7.334 7.318 7.299 7.399 7.416 7.392 7.266 7.394 7.403 7.328 7.376   7.380 7.386    
mPW1PW91 6.348 7.369 7.402 7.354 7.304 7.282 7.385 7.398 7.406 7.281 7.408 7.419 7.311 7.356   7.393 7.401    
M06-2X 6.254 7.353 7.357 7.322 7.294 7.268 7.379 7.413 7.381 7.231 7.382 7.383 7.268 7.365   7.330 7.375    
PBEPBE 6.012 7.132 7.132 7.112 7.100 7.083 7.232 7.238 7.218 7.061 7.244 7.244 7.140 7.219   7.234 7.240    
PBEPBEultrafine   7.134     7.101 7.084 7.234 7.239     7.245 7.245 7.141 7.221   7.235 7.241    
PBE1PBE 6.262 7.361 7.361 7.316 7.300 7.300 7.381 7.391 7.365 7.240 7.369 7.382 7.305 7.353   7.356 7.364    
HSEh1PBE 6.262 7.354 7.354 7.312 7.297 7.274 7.380 7.390 7.364 7.240 7.370 7.382 7.303 7.354   7.356 7.365    
TPSSh 6.320 7.354 7.354 7.297 7.279 7.259 7.358 7.367 7.343 7.227 7.352 7.361 7.288 7.336 7.353 7.336 7.350 7.357  
wB97X-D 6.297 7.318 7.318 7.274 7.252 7.237 7.329 7.349 7.327 7.196 7.313 7.330 7.264 7.286 7.296 7.302 7.294 7.301  
B97D3 6.145     7.110 7.105 7.091 7.219 7.226 7.210 7.068 7.230 7.228 7.136 7.207 7.224 7.213 7.227   7.229
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ daug-cc-pVTZ
Moller Plesset perturbation MP2 5.613 7.053 7.053 7.045 7.021 7.112 7.218 7.166 7.265 7.140 7.337 7.256 7.204 7.333   7.302 7.367 7.382  
MP2=FULL 5.611 7.053 7.053 7.044 7.019 7.110 7.217 7.165 7.264 7.132 7.335 7.257 7.201 7.318 7.364 7.300 7.357 7.378  
MP3         7.060   7.118         7.311 7.268            
MP4   7.070     7.022       7.296   7.373 7.288 7.233     7.349      
MP4=FULL   7.070     7.021       7.296       7.231 7.350   7.347      
B2PLYP 6.012 7.180 7.180 7.156 7.133 7.146 7.269 7.264 7.278 7.134 7.312 7.292 7.208 7.296   7.294 7.316    
B2PLYP=FULL 6.011 7.179 7.179 7.156 7.132 7.146 7.268 7.264 7.278 7.132 7.311 7.292 7.207 7.292   7.293 7.313    
B2PLYP=FULLultrafine 6.011 7.180 7.180 7.157 7.133 7.146 7.269 7.264 7.279 7.133 7.312 7.293 7.208 7.292   7.293 7.314    
Configuration interaction CID   7.129 7.129 7.097 7.050     7.164     7.272                
CISD   7.113 7.113 7.080 7.040     7.156     7.268                
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ daug-cc-pVTZ
Quadratic configuration interaction QCISD   7.125 7.125 7.105 7.066 7.177 7.276 7.211 7.326 7.207   7.318 7.270     7.370      
QCISD(T)         7.040     7.193     7.395 7.304 7.248     7.366      
QCISD(T)=FULL         7.040   7.260       7.392   7.246     7.362      
Coupled Cluster CCD   7.166 7.166 7.149 7.101 7.209 7.301 7.243 7.355 7.234   7.340 7.300     7.390      
CCSD         7.079         7.218   7.327 7.280 7.392   7.379      
CCSD=FULL         7.077         7.211 7.399 7.329 7.279 7.376   7.377      
CCSD(T)         7.044 7.156 7.263 7.198 7.315 7.192 7.393   7.252     7.368      
CCSD(T)=FULL         7.044             7.313 7.250            
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ daug-cc-pVTZ

Ionization Energies in eV
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 7.000 6.938 7.040 6.972 7.055 7.057     7.554
density functional B3LYP 7.347 7.304 7.433 7.396 7.346 7.344     7.905
PBEPBE                 7.697
wB97X-D 7.289 7.241 7.351 7.310 7.332 7.329      
Moller Plesset perturbation MP2 7.120 7.083 7.181 7.133 7.149 7.146     7.568
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.