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Calculated Proton Affinity

20 10 26 10 44
Name Species   Species Name
Urea NH2CONH2 CH5N2O+ urea, N-protonated

Bonding changes

Bond type H-N changed by +1
Proton Affinities (kJ/mol)
Proton Affinities in kJ/mol
Methods with predefined basis sets
composite G2 754
G3 754
G3B3 806
G4 773
CBS-Q 752

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 cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
hartree fock HF   824 824 777 801 810 793 805 809 816   800 811 807 797 801 801
density functional LSDA   856     812 817 784 801 802 816     812 794 780 784  
BLYP 1071 889 889 838 842 848 811 834 836 848   818 842 826 807 656  
B1B95 1045 850 850 802 824 779 794 778 811 823   811 817 817 803 808  
B3LYP 1057 869 869 820 829 835 805 823 825 837   810 830 817 801 806  
B3LYPultrafine   869     829 674 641 661       810 830 817 801 807  
B3PW91 1056 866 866 821 830 836 811 825 827 838   816 832 822 809 814  
mPW1PW91 1052 861 861 816 830 837 642 826 825 835   814 833 821 806 812  
M06-2X 1044 846 846 803 815 820 797 809 810 822   798 817 801 795 794  
PBEPBE 1070 880 880 832 837 843 811 830 832 843   817 837 824 807 812  
PBEPBEultrafine   719     837 687 653 674       817 837 824 807 812  
PBE1PBE 1053 860 860 814 824 824 805 820 823 833   811 827 817 804 808  
HSEh1PBE 1053 860 860 814 824 830 636 820 822 833   810 827 817 803 808  
TPSSh   874 874 829 836 843 817 833       823 839 829 815 820  
wB97X-D 905 865 865 818 829 670 809 660 826 673   816 817 823 644 815  
B97D3                     830            
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 cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
Moller Plesset perturbation MP2   891 891 833 824 838 809 823 832 830     837 815 801 801  
MP2=FULL   891 891 833 824 838 809 823 831 831     837 816 801 804  
MP3         820   813           835 816      
MP3=FULL   711 711 653 820 670 810 659 670 665     835 818 641 642  
MP4   901     831       839       844   807    
MP4=FULL   901     831       839       844   808 643  
B2PLYP   708 708 821 826 672 641 661 666 833   649 674 815 638 804  
B2PLYP=FULL   708 708 821 665 672 641 660 665 672   649 674 653 638 641  
B2PLYP=FULLultrafine   708 708 821   672 641 660 665 672   649     638    
Configuration interaction CID   869 869 814 815     816                  
CISD   870 870 815 816     817                  
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 cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
Quadratic configuration interaction QCISD   890 890 832 825 839 812 825 834 832     839 819 806 807  
QCISD(T)         828     672         842 820 806 807  
QCISD(T)=FULL         671   655           690 661 648    
Coupled Cluster CCD   885 885 828 823 836 811 823 832 830     836 818 805 807  
CCSD         824         831     838 818 805    
CCSD=FULL         824         833     838 820      
CCSD(T)         827 683   671         848 820 806    
CCSD(T)=FULL         833               848   806    
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 cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ

Proton Affinities in kJ/mol
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 770 795 773 797 769 769     803
density functional B3LYP 804 815 804 815 807 807     811
PBEPBE                 817
wB97X-D 809 662 809 662 809 809      
Moller Plesset perturbation MP2 814 810 816   816 816     809
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.