National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
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
composite G4 723

Proton Affinities in kJ/mol
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ cc-pV(T+d)Z
hartree fock HF                           789
ROHF         828                  
density functional LSDA 852     751 748   731             739
SVWN   726     748 737                
BLYP         781                 777
B1B95                           782
B3LYP                           790
B3LYPultrafine                         788  
B3PW91                           788
mPW1PW91                           791
M06-2X     780                      
PBEPBE                           770
PBE1PBE         792                  
HSEh1PBE         793                  
TPSSh         797 789     805     793    
wB97X-D     770   804 797   794   794 797 798 797  
B97D3         834     826            
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ cc-pV(T+d)Z
Moller Plesset perturbation MP2         818   799             809
MP2=FULL                         808 810
MP3           847                
MP3=FULL         830 833                
MP4                       812    
B2PLYP                       780    
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVTZ cc-pV(T+d)Z
Quadratic configuration interaction QCISD                           780
Coupled Cluster CCSD(T)                           773
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP 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.