National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
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IIExperimental data
IIICalculated data
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VCost comparisons
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XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
XVEntropy data
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XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers
XXIOddities

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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for NH3 (Ammonia)

Experimental Ionization Energy is 10.07 ± 0.02 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 10.137
G3 10.085
G3B3 10.104
G3MP2 10.102
G4 10.117
CBS-Q 10.115

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
hartree fock HF 6.632 8.000 8.000 8.302 8.411 8.401 8.544 8.439 8.447 8.441 8.507 8.383 8.508 8.549 8.571 8.571 8.572 8.508
density functional LSDA 8.485 9.919 9.919 10.358 10.553 10.579 10.848 10.686 10.724 10.648 10.836 10.575 10.845   10.925 10.959   10.845
SVWN   9.919     10.553 10.579 10.848 10.686 10.724 10.648 10.836 10.576 10.845   10.925 10.959    
BLYP 7.966 9.129 9.129 9.486 9.720 9.741 10.032 9.838 9.875 9.786 10.003 9.741 9.988     10.120   9.988
B1B95 8.039 9.238 9.238 9.596 9.786 10.072 10.026 10.132 9.906 9.869 9.973 9.809 9.978   10.060 10.070    
B3LYP 8.077 9.291 9.291 9.648 9.848 9.860 10.108 9.946 9.976 9.909 10.085 9.856 10.079 10.145 10.167 10.187 10.191 10.079
B3LYPultrafine   9.291     9.848 9.860 10.108 9.946     10.085 9.857 10.078   10.167 10.188    
B3PW91 8.084 9.303 9.303 9.637 9.825 9.837 10.044 9.908 9.936 9.889 10.017 9.836 10.023         10.023
mPW1PW91 8.021 9.240 9.258 9.584 9.750 9.757 9.966 9.824 9.867 9.826 9.949 9.760 9.938   10.035 10.045   9.938
M06-2X 8.100 9.377 18.015 9.693 9.892 9.886 10.084 9.981 10.001 9.955 10.089 9.891 10.117   10.142 10.199    
PBEPBE 8.025 9.235 9.235 9.577 9.805 9.822 10.081 9.901 9.938 9.878 10.049 9.832 10.046   10.150 10.166   10.046
PBEPBEultrafine   9.235     9.805 9.821 10.081 9.900     10.049 9.832 10.046   10.150 10.166    
PBE1PBE 7.955 9.220 9.220 9.554 9.740 10.017 9.957 9.811 9.840 9.802 9.929 9.749 9.933   10.014 10.027    
HSEh1PBE 7.950 10.032 9.212 9.544 9.729 9.737 10.849 9.804 9.832 9.790 9.923 9.737 10.745   10.005 10.019    
TPSSh   9.175 9.175 9.471 9.662 9.670 9.879 9.741   9.712 9.847 9.661 9.846   9.922 9.940    
wB97X-D     9.310   9.847   10.063   9.940   10.007 9.812 10.012     10.096    
B97D3   9.254     9.812       9.924             10.122    
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
Moller Plesset perturbation MP2 6.927 8.646 8.646 9.067 9.484 9.600 9.830 9.549 9.743 9.849 9.834 9.623 10.056 10.202 10.033 10.206 10.264 10.056
MP2=FULL 6.927 8.648 8.648 9.069 9.488 9.605 9.835 9.556 9.749 9.856 9.839 9.628 10.059 10.211 10.037 10.212 10.273 10.059
MP3         9.372   9.711       9.695 9.522 9.912          
MP3=FULL         9.374   9.697       9.698 9.525 9.913          
MP4   8.620     9.416       9.694   9.782 9.568 10.009   9.981 10.157    
MP4=FULL   8.621     9.418       9.698     9.572 10.010   9.984 10.162    
B2PLYP 7.630 9.018 9.018 9.392 9.653 9.693 9.933 9.735 9.814 9.805 9.919 9.699 9.982   10.042 10.105    
B2PLYP=FULL 7.630 9.019 9.019 9.393 9.654 9.695 9.935 9.737 9.815 9.807 9.920 9.701 9.983   10.043 10.107    
Configuration interaction CID   8.520 8.520 8.902 9.276     9.330                    
CISD     8.519 8.897 9.277     9.334                    
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
Quadratic configuration interaction QCISD   8.566 8.566 8.956 9.368 9.478 9.684 9.430 9.606 9.713 9.686 9.500 9.885   9.876 10.014    
QCISD(T)         9.390           9.744 9.542 9.966   9.946 10.109    
QCISD(T)=FULL         9.392   9.730         9.545 9.967 10.108 9.948 10.113 10.162  
QCISD(TQ)         9.390   9.725         9.542 9.958   9.942 10.098    
QCISD(TQ)=FULL         9.393   9.729         9.546 9.959   9.945 10.103    
Coupled Cluster CCD   8.567 8.567 8.960 9.365 9.478 9.677 9.424 9.603 9.714 9.678 9.499 9.881   9.865 10.007    
CCSD         9.364         9.711 9.680 9.498 9.880 10.001 9.870 10.008 10.050  
CCSD=FULL         9.366         9.716 9.684 9.501 9.882 10.009 9.873 10.013    
CCSD(T)         9.388           9.741 9.541 9.964 10.098 9.943 10.106    
CCSD(T)=FULL         9.391           9.745 9.544 9.965 10.106 9.946 10.111 10.160  
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

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 8.306 8.417 8.362 8.463 8.385 8.387
density functional B3LYP 9.623 9.789 9.709 9.874 9.768 9.765
Moller Plesset perturbation MP2 9.118 9.533 9.240 9.626 9.224 9.228
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.