National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
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XIXIndex of properties
XXH-bond dimers
XXIOddities

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III.D.11.

Calculated Proton Affinity

Name Species   Species Name
Acetylene C2H2 C2H3+ vinyl cation

Bonding changes

Bond type H-C changed by +2
Bond type C#C lost 1
Bond type C=C gained 1
Proton Affinities (kJ/mol)
Proton Affinities in kJ/mol
Methods with predefined basis sets
composite G4 621
CBS-Q 617

Proton Affinities in kJ/mol
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 aug-cc-pVQZ
hartree fock HF 792 660 660 680 683 690   671 675 688 658 681 675 675 677 675 675
density functional LSDA 721 610 610 625 635 644 628 615 625 646   634 627 611 628 627 611
SVWN   585     635   628       622            
BLYP 751 645 645 660 664 668 648 641 644 663   652 643        
B1B95 734 632 632 649 655 662 648 639 648 665   654 654 644 652 654 644
B3LYP 749 641 641 657 661 667 649 641 645 665 641 652 646 643 645 645 643
B3LYPultrafine         662                     643  
B3PW91 744 638 638 656 660 667 654 644 653 670   659 656        
mPW1PW91 744 639 637 655 661 669 655 645 654 670   662 659        
M06-2X     643   643                        
PBEPBE 741 636 636 652 655 664 647 637 648 666   654 649 639 647   639
PBE1PBE         654                        
HSEh1PBE   599     654               653        
TPSSh         667   658     673     658        
wB97X-D     640   664   655   655   653 655 659     659  
B97D3   655     675       661             661  
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 aug-cc-pVQZ
Moller Plesset perturbation MP2 701 589 589 600 625 648   612 634 641 634 636 631   627 629  
MP2=FULL 701 589 589 600 625 648 635 612 634 641   636 633     598  
MP3         643                        
MP3=FULL         642   653                    
MP4   613     636       645                
Configuration interaction CID   622 622 638 645     635                  
CISD     627 643 648     634                  
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 aug-cc-pVQZ
Quadratic configuration interaction QCISD   621 621 636 643 661 646 629 649 656   651 647        
QCISD(T)         637             649 643   641 641  
Coupled Cluster CCD   613 613 627 640 663 651 630 651 657   652 648   645 647  
CCSD         642                        
CCSD(T)         636   646         649 627   641 641  
CCSD(T)=FULL         636               645        
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 aug-cc-pVQZ

Proton Affinities in kJ/mol
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 693 699 671 675 669 668
density functional B3LYP 668 675 652 656 645 646
Moller Plesset perturbation MP2 607 634 590 621 585 584
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.