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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XIXIndex of properties
XXH-bond dimers
XXIOddities

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

Calculated Ionization Energy for C3H3 (Propargyl radical)

Experimental Ionization Energy is 8.67 ± 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
semi-empirical PM3  
PM6  
composite G3 8.815
G4 8.805
CBS-Q 8.815

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
hartree fock HF 7.220 8.386 8.386 8.315 8.242 8.236 8.341 8.334 8.333 8.203 8.344 8.316 8.322 8.329 8.351 8.328
ROHF         7.794 7.789 7.911 7.904       7.870 7.901      
density functional LSDA 7.603 9.057 9.057 8.963 8.974 8.982 9.160 9.183 9.192 8.993   9.099 9.202   9.192  
SVWN   9.057     8.974   9.160       9.208          
BLYP 7.004 8.275 8.275 8.200 8.202 8.206 8.424 8.414 8.420 8.218   8.336 8.446      
B1B95 7.282 8.568 8.568 8.477 8.423 8.468 8.620 8.777 8.621 8.462   8.567 8.581   8.592  
B3LYP 7.312 8.577 8.577 8.493 8.490 8.493 8.676 8.673 8.680 8.496 8.710 8.611 8.696   8.704 8.712
B3LYPultrafine         8.490                     8.712
B3PW91 7.437 8.735 8.735 8.614 8.620 8.622 8.761 8.767 8.772 8.620   8.720 8.777      
mPW1PW91 7.461 8.725 8.756 8.635 8.610 8.611 8.755 8.750 8.784 8.637   8.708 8.764      
M06-2X     8.558   8.558                      
PBEPBE 7.199 8.537 8.537 8.434 8.445 8.447 8.629 8.617 8.621 8.453   8.561 8.647      
PBE1PBE         8.616                      
HSEh1PBE   9.901     9.785   9.927           9.936      
TPSSh         8.497   8.642     8.496     8.662      
wB97X-D     8.662   8.537       8.694       8.683     8.694
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
Moller Plesset perturbation MP2 5.918 7.790 7.790 7.658 7.828 7.887 8.069 8.059 8.134 8.038 8.143 8.050 8.290   8.190  
MP2=FULL 5.924 7.790     7.837 7.896 8.079 8.068 8.144     8.056        
MP3         8.002                      
MP3=FULL         8.009                      
MP4         7.843                      
B2PLYP         8.273               8.553      
Configuration interaction CID         8.096                      
CISD         8.136                      
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
Quadratic configuration interaction QCISD   8.264     8.251 8.299 8.448 8.455 8.512     8.464        
Coupled Cluster CCD         8.065             8.274        
CCSD         8.261                      
CCSD(T)         8.159                      
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

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 8.425 8.321 8.446 8.327 8.468 8.472
density functional B3LYP 8.592 8.573 8.665 8.643 8.680 8.675
Moller Plesset perturbation MP2 7.647 7.823 7.814 7.994 7.807 7.809
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.