National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 22May 2022
NIST Standard Reference Database 101
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XVII.C.1. (III.D.6.)

Calculated Ionization Energy for NNH (Dinitrogen monohydride)

Experimental Ionization Energy is 7.8 ± 0.05 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
composite G2 8.253
G3 8.312
G3B3 8.279
G4 8.267
CBS-Q 8.315

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) 6-311+G(3df,2p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ daug-cc-pVTZ
hartree fock HF 8.023 8.003 8.003 8.271 7.834 8.073 8.136 8.030 8.006 7.951 7.995 7.968 8.006 7.947 8.173 7.987 7.978
density functional LSDA 7.884 8.532 8.532 8.804 8.854 8.836 8.983 8.858 8.834 8.764     8.739 8.834 9.009    
BLYP 7.620 8.070 8.070 8.340 8.376 8.354 8.533 8.373 8.349 8.285     8.253 8.359      
B1B95 7.663 8.108 8.108 8.324 8.332 8.417 8.426 8.298 8.277 8.234     8.227 8.260 8.450 8.323  
B3LYP 7.854 8.287 8.287 8.554   8.547 8.690 8.546 8.524 8.467   8.560 8.452 8.518 8.713 8.590  
B3LYPultrafine         8.568                     8.590  
B3PW91 7.874 8.354 8.354 8.550 8.567 8.546 8.649 8.536 8.512 8.470     8.466 8.492      
mPW1PW91 7.874 8.353 8.353 8.543 8.554 8.532 8.638 8.519 8.494 8.457     8.455 8.477      
M06-2X     8.144   8.308           8.346            
PBEPBE 7.643 8.182 8.182 8.386 8.426 8.404 8.553 8.414 8.391 8.346     8.321 8.401   7.828  
PBEPBEultrafine         8.426                        
PBE1PBE         8.502                        
HSEh1PBE   8.287     8.502   8.590             8.438      
TPSSh         8.500   8.582     8.400       8.438      
wB97X-D     8.235   8.461   8.543   8.390     8.377 8.543 8.336   8.389  
B97D3   8.239     8.429   8.538   8.389   8.454 8.423   8.378   8.451 8.448
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 4.520 6.445 6.445 6.663 7.224 7.262 7.394 7.247 7.282 7.390   7.305 7.203   7.537 7.608  
MP2=FULL 4.516 6.442 6.442 6.661 7.222 7.259 7.391 7.248 7.282 7.388     7.201 7.479      
MP3         -0.393                        
MP3=FULL         7.700   7.857                    
MP4   6.764     7.469                        
B2PLYP         8.166                 8.202      
B2PLYP=FULLultrafine         8.165               8.080 8.192   8.281  
Configuration interaction CID   7.121 7.121 7.411 7.709     7.705                  
CISD   7.294 7.294 7.605 7.801     7.784                  
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   7.385 7.385 7.708 7.901 7.935 8.058 7.890 7.922 8.005     7.878 8.082      
QCISD(T)         7.842                        
Coupled Cluster CCD   6.987 6.987 7.274 7.633 7.671 7.788 7.644 7.677 7.773     7.614 7.864      
CCSD         7.889       7.910                
CCSD(T)         7.827       7.851                
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

Ionization Energies in eV
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 8.675 8.433 8.583 8.148 8.412 8.413     7.957
density functional B3LYP 8.910 8.871 8.859 8.729 8.681 8.674     8.559
PBEPBE                 8.446
Moller Plesset perturbation MP2 6.665 7.278 6.717 7.295 6.577 6.575     7.533
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.