National Institute of Standards and Technology

Computational Chemistry Comparison and Benchmark DataBase
Release 22	May 2022
NIST Standard Reference Database 101

I	Introduction
II	Experimental data
III	Calculated data
IV	Data comparisons
V	Cost comparisons
VI	Input and output files
VII	Tutorials and Units
VIII	Links to other sites
IX	Feedback
X	Older CCCBDB versions
XII	Geometries
XIII	Vibrations
XIV	Reaction data
XV	Entropy data
XVI	Bibliographic data
XVII	Ion data
XVIII	Bad calculations
XIX	Index of properties
XX	H-bond dimers
XXI	Oddities

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

Calculated Ionization Energy for H (Hydrogen atom)

Experimental Ionization Energy is 13.59844 eV

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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

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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)	TZVP	cc-pVDZ	cc-pVTZ	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	cc-pV(T+d)Z	cc-pCVDZ	cc-pCVTZ	daug-cc-pVTZ
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			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	12.621	13.424	13.424	13.503	13.503	13.503	13.503	13.553	13.553	13.503	13.553			13.530	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	13.579	13.579	13.653	13.653	13.653	13.653	13.705	13.705	13.653				13.685	13.705		13.694		13.712	13.703
	M06-2X			13.415
	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		13.536					13.595						13.600
	TPSSh					13.548		13.548			13.548					13.602
	wB97X-D			13.548		13.622		13.622		13.678				13.678	13.657	13.678			13.682
	B97D3		13.536			13.605		13.605		13.673		13.673		13.672		13.673			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)	TZVP	cc-pVDZ	cc-pVTZ	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	cc-pV(T+d)Z	cc-pCVDZ	cc-pCVTZ	daug-cc-pVTZ
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	13.601	13.601
	MP2=FULL		13.502			13.558	13.558	13.558	13.601	13.601					13.586	13.601		13.588			13.601	13.601	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)	TZVP	cc-pVDZ	cc-pVTZ	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	cc-pV(T+d)Z	cc-pCVDZ	cc-pCVTZ	daug-cc-pVTZ
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)	TZVP	cc-pVDZ	cc-pVTZ	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	cc-pV(T+d)Z	cc-pCVDZ	cc-pCVTZ	daug-cc-pVTZ

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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	13.541	13.541	13.601	13.601	13.541	13.541			13.601
density functional	B1B95	13.467	13.464		13.552
	B3LYP	13.576	13.576	13.664	13.664	13.576	13.576			13.664
	B3LYPultrafine				13.664	13.576
	PBEPBE									13.595
Moller Plesset perturbation	MP2	13.541	13.541	13.601	13.601	13.541	13.541			13.601
	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.