National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIntroduction
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
IXFeedback
XOlder CCCBDB versions
XIIGeometries
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
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 H (Hydrogen atom)

Experimental Ionization Energy is 13.59844 eV
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  
composite G1 13.606
G2MP2 13.606
G2 13.606
G3 13.633
G3B3 13.635
G4 13.644
CBS-Q 13.601

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) 6-311+G(3df,2pd) cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
hartree fock HF 12.696 13.502 13.502 13.558 13.558 13.558 13.558 13.601 13.601 13.558 13.601 13.601 13.586 13.601 13.604 13.588 13.601 13.604 13.601    
ROHF   13.502 13.502   13.558 13.558 13.558 13.601         13.586 13.601         13.601    
density functional LSDA 12.359 13.357 13.357 13.441 13.441 13.441 13.441 13.500 13.500 13.441     13.477 13.500   13.490     13.500    
BLYP 12.592 13.393 13.393 13.482 13.482 13.482 13.482 13.539 13.539 13.482     13.508 13.539   13.524     13.539    
B1B95 12.618 13.420 13.420 13.501 13.501 13.501 13.501 13.552 13.552 13.501 13.552   13.527 13.553   13.540     13.553 13.552 13.552
B3LYP 12.722 13.533 13.533 13.613 13.613 13.613 13.613 13.664 13.664 13.613 13.664 13.664 13.640 13.664 13.670 13.651 13.667 13.671 13.664 13.640 13.664
B3LYPultrafine   13.533 13.533 13.613 13.613 13.613 13.613 13.664 13.664 13.613 13.664 13.664 13.640 13.664     13.667        
B3PW91 12.782 13.591 13.591 13.665 13.665 13.665 13.665 13.714 13.714 13.665     13.694 13.714   13.702     13.714    
mPW1PW91 12.783 13.576 13.579 13.653 13.650 13.650 13.650 13.703 13.705 13.653     13.682 13.703   13.694   13.712 13.703    
M06-2X     13.515                                    
PBEPBE 12.636 13.453 13.453 13.536 13.536 13.536 13.536 13.595 13.595 13.536 13.595 13.595 13.568 13.595   13.585 13.600   13.595 13.552 13.552
PBEPBEultrafine   13.453     13.536   13.453         13.595         13.600        
TPSSh         13.548   13.548     13.548       13.602              
wB97X-D     13.548   13.622       13.678         13.678     13.682        
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) 6-311+G(3df,2pd) cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
Moller Plesset perturbation HF MP2 12.696 13.502 13.502 13.558 13.558 13.558 13.558 13.601 13.601 13.558 13.601 13.601 13.586 13.601   13.588 13.601   13.601 13.586 13.601
MP2=FULL   13.502     13.558 13.558 13.558 13.601 13.601       13.586 13.601   13.588     13.601 13.586 13.601
PMP2         13.558   13.558                            
HF MP3         13.558               13.586 13.601         13.601    
HF MP4   13.502 13.502 13.558 13.558     13.601     13.601     13.601   13.588 13.601        
B2PLYP                           13.568              
Configuration interaction HF CID         13.558     13.601           13.601         13.601    
HF CISD   13.502     13.558                 13.601         13.601    
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) 6-311+G(3df,2pd) cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ
Quadratic configuration interaction HF QCISD   13.502   13.558 13.558 13.558 13.558 13.601         13.586 13.601         13.601 13.601 13.601
HF QCISD(T)   13.502 13.502 13.558 13.558 13.558 13.558 13.601         13.586 13.601         13.601    
Coupled Cluster HF CCD   13.502 13.502 13.558 13.558 13.558 13.558 13.601     13.601   13.586 13.601 13.604 13.588 13.601 13.604 13.601    
HF CCSD   13.502 13.502 13.558 13.558 13.558 13.558 13.601     13.601   13.586 13.601   13.588 13.601   13.601    
HF CCSD(T)   13.502 13.502 13.558 13.558 13.558 13.558 13.601     13.601 13.601 13.586 13.601   13.588 13.601   13.601 13.586 13.601
CCSD(T)=FULL         13.558   13.558           13.586 13.601   13.588 13.601   13.601 13.586 13.601
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) 6-311+G(3df,2pd) cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z cc-pCVDZ 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 13.541 13.541 13.601 13.601 13.541 13.541
density functional B1B95 13.464 13.464   13.552    
B3LYP 13.576 13.576 13.664 13.664 13.576 13.576
B3LYPultrafine       13.664 13.576  
Moller Plesset perturbation MP2 13.541 13.541 13.601 13.601 13.541 13.541
ROMP2 13.541   13.601   13.541 13.541
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.