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 Ca (Calcium atom)

Experimental Ionization Energy is 6.11316 ± 0.00002 eV

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Ionization Energies in eV

Methods with predefined basis sets

semi-empirical	PM3
	PM6
composite	G1	6.190
	G2MP2	6.208
	G2	6.173
	G3B3	6.196
	G3MP2	6.265
	G4	6.065

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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)	TZVP	cc-pVDZ	cc-pVTZ
hartree fock	HF	4.014	5.118	5.108	5.128	5.122	5.122	5.122	5.119	5.119	5.119		5.119
density functional	LSDA	5.937	6.133	6.615	6.670	6.638	6.638	6.638	6.648	6.648	6.635
	BLYP	5.284	6.103	6.063	6.092	6.062	6.062	6.062	6.070	6.070	6.061
	B1B95			5.885	226.304			5.908	5.911	5.911
	B3LYP	5.352		6.148	6.179	6.151	6.151	6.150	6.156	6.156	6.148		6.146
	B3PW91	5.220	6.023	5.983	6.032	6.005	6.005	6.005	6.006	6.006	6.004
	mPW1PW91	5.168	6.012	5.973	6.011	5.983	5.983	5.983	5.983	5.983	5.983
	M06-2X			6.314
	PBEPBE	5.298	6.113	6.068	6.111	6.079	6.079	6.078	6.083	6.083	6.077
	PBE1PBE					6.003
	TPSSh					5.978		5.978			5.979				5.964
	wB97X-D			6.017		6.074		6.074		6.072			6.061	6.074	6.058
	B97D3		6.576			6.549		6.549		6.543		6.457	6.533		6.537
		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
Moller Plesset perturbation	MP2	4.441	5.499	5.595	5.511	5.659	5.659	5.660	5.779	5.779	5.796		5.520
	MP2=FULL	4.445	5.504	5.631	5.511	5.659	5.659	5.660	5.782	5.782	5.796
	MP3							5.812
	MP3=FULL					5.812		5.812
	MP4		5.782			5.871				5.955
	B2PLYP														5.954
Configuration interaction	CID		5.830			5.858
	CISD		5.831			5.865
		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
Quadratic configuration interaction	QCISD		5.831		5.816	5.884	5.884	5.885	5.935	5.935	5.927
	QCISD(T)					5.897
Coupled Cluster	CCD		5.830		5.815	5.876	5.876	5.877	5.917	5.917	5.914
	CCSD					5.884
	CCSD(T)					5.897
		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

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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	5.295		5.295		5.311	5.153			5.119
density functional	B3LYP	6.109		6.109		6.439	6.208			6.146
	PBEPBE									6.076
Moller Plesset perturbation	MP2	5.694		5.694		5.690	5.888			5.623

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.