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Calculated Proton Affinity

15 11 04 06 09
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 G1  
G2MP2  
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         747         743       789
ROHF         828                  
density functional LSDA 852     751 748   731             739
SVWN   726     748 737       777        
BLYP         781                 777
B1B95                           782
B3LYP                   749       790
B3LYPultrafine                         788  
B3PW91                           788
mPW1PW91                           791
M06-2X     780   740                  
PBEPBE                           770
PBE1PBE         792                  
HSEh1PBE   769     793 678           764    
TPSSh         797 789     805     793    
wB97X-D     770   804 797   794   794 797 798 797  
B97D3   744     834     826         763  
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     767       809
MP2=FULL                         808 810
MP3           847                
MP3=FULL         830 833                
MP4                       812    
B2PLYP         753             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.