National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 19April 2018
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
IXFeedback
XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

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III.D.11.

Calculated Proton Affinity

Name Species   Species Name
Ethynyl radical C2H C2H2+ acetylene cation

Bonding changes

Bond type H-C changed by +1
Proton Affinities (kJ/mol)
Proton Affinities in kJ/mol
Methods with predefined basis sets

Proton Affinities in kJ/mol
Methods with standard basis sets
3-21G 3-21G* 6-31G* 6-31+G** 6-311G* 6-311G** 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF                 789       789
ROHF     828                    
density functional BLYP                         777
B1B95                         782
B3LYP                 788       790
B3LYPultrafine                       788  
B3PW91                         788
mPW1PW91                         791
M06-2X   751                      
PBEPBE                         770
PBE1PBE     792                    
HSEh1PBE     793                    
TPSSh                     793    
wB97X-D   770 804 797   794   794   797 798 797  
B97D3     834 820   826 824       803    
3-21G 3-21G* 6-31G* 6-31+G** 6-311G* 6-311G** 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2     818   799       807       809
MP2=FULL                       808 810
MP3       847                  
MP3=FULL     830 833                  
MP4                     812    
B2PLYP                     780    
3-21G 3-21G* 6-31G* 6-31+G** 6-311G* 6-311G** 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ aug-cc-pVTZ cc-pV(T+d)Z
Quadratic configuration interaction QCISD                         780
Coupled Cluster CCSD(T)                         773
3-21G 3-21G* 6-31G* 6-31+G** 6-311G* 6-311G** 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ aug-cc-pVTZ cc-pV(T+d)Z
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.