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Calculated Ionization Energy for H2S2 (Disulfane)

Experimental Ionization Energy is 9.3 eV
Please note! These calculated ionizataion energies have the vibrational zero-point energy (zpe) included, but the zpe has NOT been scaled. Click on an entry for more details, including the ionization energy with a scaled zpe.
Original data displayed. Press to display differences.
Differences displayed. Press to display original data.

Ionization Energies in eV
Methods with predefined basis sets
semi-empirical AM1  
PM3  
PM6  
composite G2 9.103
G3 9.110
G3B3 9.113
G4 9.097
CBS-Q 9.099

Ionization Energies in eV
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 cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVTZ
hartree fock HF 5.849 9.306 8.556 9.148 8.497 8.488 8.473 8.489 8.481 8.286 8.408 8.382 8.262 8.243 8.365 8.267 8.246 8.234 8.239 8.235
density functional LSDA 6.133 2.676 9.438 9.647 9.404 9.402 9.420 9.441 9.445 9.338 9.409 9.316 9.386   9.408 9.399   9.378 9.391 9.372
SVWN   9.731     9.404 9.402 9.420 9.441 9.445 9.338   9.316 9.386   9.408 9.399   9.378 9.391 9.372
BLYP 5.559 8.985 8.686 8.926 8.673 8.668 8.721 8.759 8.760 8.594 8.692 8.575 8.653   8.703 8.683   8.644 8.674 8.638
B1B95 6.052 2.810 8.976 9.276 8.922 9.087   9.170 8.934 8.824 8.881 8.837 8.834   8.883 8.850   8.821 8.837 8.817
B3LYP 6.012 9.413 9.019 9.326 8.991 8.986 9.013 9.042 9.042 8.892 8.982 8.895 8.928 8.928 8.981 8.948 8.936 8.915 8.934 8.911
B3LYPultrafine   9.412     8.990 8.984 9.012 9.041     8.980 8.893 8.926   8.979 8.946   8.913 8.932 8.909
B3PW91 6.074 9.494 9.092 9.368 9.029 9.024 9.023 9.031 9.031 8.921 8.986 8.950 8.931   8.985 8.940   8.918 8.927 8.913
mPW1PW91 6.099 9.517 9.090 9.388 9.027 9.022 9.024 9.036 9.035 8.911 8.981 8.946 8.920   8.981 8.933   8.906 8.919 8.902
M06-2X 6.255 9.629 110.026 9.565 9.181 9.168 9.168 9.186 9.176 9.065 9.132 9.048 9.079   9.092 9.087   9.066 9.075 9.067
PBEPBE 5.670 9.161 8.853 9.076 8.818 8.812 8.838 8.863 8.864 8.730 8.798 8.727 8.760   8.809 8.785   8.752 8.777 8.746
PBEPBEultrafine   9.164     8.818 8.813 8.838 8.864     8.799 8.727 8.760   8.810 8.785   8.752 8.777 8.746
PBE1PBE 6.018 9.055 9.055 9.361 9.001 9.001 8.996 9.010 9.009 8.884 8.951 8.911 8.891   8.948 8.906   8.878 8.892 8.874
HSEh1PBE 6.010 9.465 9.045 9.346 8.990 8.984 8.987 9.003 9.002 8.876 8.945 8.901 8.886   8.942 8.899   8.872 8.886 8.868
TPSSh 5.957 9.390 8.997 9.273 8.939 8.932 8.934 8.958 8.953 8.830 8.895 8.852 8.841 8.836 8.886 8.856 8.845 8.830 8.845 8.824
wB97X-D 6.208 9.625 9.179 9.485 9.109 9.108 9.105 9.100 9.105 8.996 9.066 7.926 8.995 8.992 9.075 9.003 8.998 8.977 8.985 8.972
B97D3 5.860 9.157 8.824 9.052 8.776 8.772 8.799 8.827 8.828 8.688 8.771 8.701 8.728 8.732 8.782 8.750 8.742      
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 cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVTZ
Moller Plesset perturbation MP2 5.160 8.865 8.654 8.814 8.634 8.670 8.672 8.653 8.708 8.882 8.693 8.677 8.934 9.030 8.887 9.009 9.062 8.922 8.999 8.927
MP2=FULL 5.151 8.863 8.653 8.813 8.632 8.668 8.670 8.653 8.708 8.881 8.687 8.677 8.926 9.031 8.888 9.001 9.064 8.920 8.996 8.942
MP3         8.663   8.607       8.725 8.715 8.975         8.963 9.034 8.967
MP3=FULL   8.984 8.686 8.909 8.659 8.695 8.696 8.675 8.733 8.916 8.717 8.713 8.961   8.916 9.030   8.946 9.016 8.968
MP4   8.927     8.615       8.687   8.669 8.655 8.943   8.881 9.027   8.933 9.018 8.937
MP4=FULL   8.925     8.611       8.683     8.652 8.930   8.881 9.014   8.919 9.004 8.940
B2PLYP 5.719 9.203 8.855 9.130 8.830 8.836 8.854 8.866 8.881 8.837 8.834 8.775 8.871   8.902 8.911   8.858 8.898 8.857
B2PLYP=FULL 5.716 9.202 8.855 9.130 8.829 8.836 8.853 8.866 8.881 8.836 8.832 8.775 8.868   8.902 8.908   8.856 8.897 8.860
B2PLYP=FULLultrafine 5.994 9.420 8.861 9.304 8.824 8.817 8.825 8.848 8.844 8.682 8.780 8.720 8.694   8.765 8.707   8.673 8.687 8.672
Configuration interaction CID   9.073 8.684 8.980 8.647     8.655                   8.805 8.853 8.808
CISD   9.050 8.667 8.961 8.629     8.639                   8.781 8.830  
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 cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVTZ
Quadratic configuration interaction QCISD   8.996 8.690 8.924 8.660 8.692 8.696 8.675 8.729 8.896 8.715 8.703 8.939   8.887 9.003   8.924 8.989 8.927
QCISD(T)         8.614     8.630     8.666 8.652 8.925   8.869 9.006   8.913 8.995 8.917
QCISD(T)=FULL         8.610   8.650         8.649 8.913 9.020 8.869 8.993 9.050 8.899 8.980 8.919
QCISD(TQ)         8.611   8.650         8.648 8.922   8.864          
QCISD(TQ)=FULL         8.607   8.646         8.645                
Coupled Cluster CCD   9.033 8.719 8.954 8.691 8.725 8.725 8.703 8.758 8.940 8.747 8.736 8.983   8.922 9.047   8.969 9.034 8.973
CCSD         8.663         8.901 8.719 8.708 8.943 9.027 8.891 9.007   8.928 8.993 8.932
CCSD=FULL         8.660         8.892 8.712 8.706 8.931 9.020 8.891 8.994   8.915 8.979 8.939
CCSD(T)         8.617 8.651 8.657 8.633 8.688 8.878 8.669 8.655 8.928 9.030 8.872 9.009 9.060 8.916 8.998 8.920
CCSD(T)=FULL         8.613           8.661 8.652 8.916 9.023 8.872 8.996   8.903 8.983 8.924
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 cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVTZ

Ionization Energies in eV
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 9.080 8.386 9.054 8.380 9.275 9.215
density functional B3LYP 9.307 8.929 9.270 8.915 9.437 9.358
wB97X-D 9.390 8.962 9.353 8.949 9.604 9.583
Moller Plesset perturbation MP2 8.760 8.618 8.764 8.641 8.854 8.777
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.