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Calculated Proton Affinity

20 10 26 10 44
Name Species   Species Name
Urea NH2CONH2 H2NCOHNH2+ urea, protonated

Bonding changes

Bond type C=O lost 1
Bond type H-O gained 1
Bond type O-C gained 1
Proton Affinities (kJ/mol)
Proton Affinities in kJ/mol
Methods with predefined basis sets
composite G2 817
G3 821
G3B3 871
G4 838
CBS-Q 817

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 1117 912 912 885 884 904 887 878 898 910   889 901 900 887 894 894
density functional LSDA                   888       866 851 856  
BLYP 1089     878           900     892 877 860 709  
B1B95 1089 895 895 866 882 837 862 827 876 894   875 885 887 874 879  
B3LYP 1096 908 908 879 882 898 868 868 885 903   870 894 883 868 873  
B3LYPultrafine   908     882 737 705         870 895 883 868 873  
B3PW91 1095 907 907 881 885 901 876 871 889 906   878 897 890 877 882  
mPW1PW91 1097 907 907 880 888 905 710 875 890 906   879 901 892 876 882  
M06-2X 1097 898 898 874 875 891 867 860 877 896   865 888 876 868 868  
PBEPBE 1092     876           900     891 880 864 869  
PBEPBEultrafine                           880 864 869  
PBE1PBE 1099 905 905 878 881 881 873 869 888 904   876 895 888 874 879  
HSEh1PBE 1098 905 905 878 881 898 704 869 887 904   875 895 887 873 879  
TPSSh   907 907 881 883 900 875         878 897 889 875 881  
wB97X-D 950 911 911 884 887 738 877 709 891 744   881 886 893 714 885  
B97D3                     883            
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 1099 904 904 867 865 889       886     886 874 854 859  
MP2=FULL 1099 904 904 867 865 890       887     887 877 854 862  
MP3         880               902 892      
MP3=FULL   754 754 717 880 741 881 709 739 737     903 896 711 716  
MP4   908                     889 876 857 861  
MP4=FULL   908                     890 881 857    
B2PLYP 960 739 739 872 874 731 701   722 895     732 878 700 867  
B2PLYP=FULL 960 739 739 872 714 731 701   722 734     732 717 700 705  
B2PLYP=FULLultrafine 960 739 739 872   731 701   722 734         700    
Configuration interaction CID   919 919 885 881     873                  
CISD   918 918 884 880     872                  
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   918 918 882 875 900       897     897 887 867 874  
QCISD(T)                         895 882 863 869  
QCISD(T)=FULL                         743   706    
Coupled Cluster CCD   920 920 884 878 902 877 868 895 899     900 890 871    
CCSD         877         898     898 888 869    
CCSD=FULL         877         900     899 892 870    
CCSD(T)                         901 883 863 706  
CCSD(T)=FULL                         902 887 864    
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 880 874 878 873 882 881     897
density functional B3LYP 867   865   871 871     878
PBEPBE                 875
wB97X-D 878   874   879 879      
Moller Plesset perturbation MP2 852   850   852 852     868
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.