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Calculated Proton Affinity

15 11 04 06 09
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 G1  
G2MP2  
G2 547
G3 543
G3B3 548
G3MP2  
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) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
hartree fock HF 792 660 660 680 683 690 600 671 675 688   658 674 681 675 675 677 675 675
density functional LSDA                               611   627 611
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   641 645 652 646 643 645 645 643
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     616   643                            
PBEPBE 741 636 636 652 655 664 647 637 648 666     648 654 649 639 647   639
PBE1PBE         654                            
HSEh1PBE         654   580               653        
TPSSh         667   658     673         658        
wB97X-D     640   664   655   655     653   655 659     659  
B97D3   655     675   664   661   660       662     661  
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
Moller Plesset perturbation MP2 701 589 589 600 625 648 566 612 634 641   634 630 636 631   627 629  
MP2=FULL 701 589 589 600 625 648 635 612 634 641       636 633        
MP3         643                            
MP3=FULL         642   653                        
MP4   613     636       645                    
Configuration interaction CID   622 622 638 645     635                      
CISD   556 627 643 648     634                      
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP 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) 6-311+G(3df,2p) TZVP Def2TZVPP 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)
daug-cc-pVDZ daug-cc-pVTZ daug-cc-pVQZ Sadlej_pVTZ 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.