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 Ar (Argon atom)

Experimental Ionization Energy is 15.759 ± 0.001 eV

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Ionization Energies in eV

Methods with predefined basis sets

semi-empirical	PM6
composite	G1	15.731
	G2MP2	15.686
	G2	15.694
	G3	15.690
	G3B3	15.703
	G3MP2	15.719
	G4	15.719
	CBS-Q	15.791

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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	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	daug-cc-pVTZ
hartree fock	HF	13.495	14.823	14.710	14.775	14.659	14.659	14.661	14.655	14.655	14.579		14.655	14.680	14.576	14.554	14.684	14.568	14.552	14.565
density functional	LSDA	15.247	12.979	16.561	16.528	16.537	16.537	16.548	16.597	16.597	16.452			16.536	16.600		16.611	16.603
	BLYP	14.346	15.617	15.568	15.606	15.563	15.563	15.648	15.636	15.636	15.517			15.556	15.589
	B1B95	14.760		15.763	15.771	15.752	15.730	15.769	15.761	15.761	15.687			15.739	15.736		15.810	15.740
	B3LYP	14.625	15.856	15.807	15.835	15.790	15.790	15.848	15.839	15.839	15.745		15.835	15.791	15.793	15.789	15.865	15.801	15.791
	B3LYPultrafine					15.789												15.801
	B3PW91	14.766	15.911	15.852	15.865	15.815	15.815	15.845	15.844	15.844	15.765			15.830	15.792
	mPW1PW91	14.739	15.853	15.810	15.830	15.757	15.757	15.790	15.789	15.808	15.724			15.772	15.731		15.831	15.753
	M06-2X			15.871
	PBEPBE	14.577	15.775	15.717	15.750	15.702	15.702	15.765	15.754	15.754	15.657			15.707	15.702		15.780	15.716
	PBE1PBE					15.750
	TPSSh					15.724		15.757			15.673				15.708
	wB97X-D			15.869		15.801		15.824		15.828			15.821	15.824	15.776			15.776
	B97D3		15.767			15.677		15.731		15.736		15.696	15.726		15.679			15.690
		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	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	daug-cc-pVTZ
Moller Plesset perturbation	MP2	13.495	15.225	15.390	15.176	15.346	15.346	15.355	15.352	15.352	15.665		15.457	15.434	15.680	15.813	15.657	15.741	15.844
	MP2=FULL	13.495	15.225	15.392	15.176	15.346	15.346	15.355	15.346	15.346	15.676			15.437	15.683	15.822	15.659	15.745	15.853
	MP3					15.263		15.318
	MP3=FULL					15.258		15.265
	MP4		15.247			15.235				15.234					15.568
Configuration interaction	CID		15.232	15.227	15.190	15.187			15.180
	CISD		15.232	15.219	15.193	15.177			15.173
		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	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	daug-cc-pVTZ
Quadratic configuration interaction	QCISD		15.247	15.255	15.207	15.214	15.214	15.224	15.211	15.211	15.496			15.292	15.503		15.505	15.556
	QCISD(T)					15.222								15.294	15.543
Coupled Cluster	CCD		15.246	15.265	15.204	15.225	15.225	15.233	15.219	15.219	15.514			15.304	15.520		15.516	15.573
	CCSD					15.215								15.293	15.504
	CCSD(T)					15.223								15.294	15.544	15.707	15.527	15.612	15.738
	CCSD(T)=FULL					15.220								15.294	15.541	15.707	15.526	15.609	15.738
		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	cc-pVQZ	aug-cc-pVDZ	aug-cc-pVTZ	aug-cc-pVQZ	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	14.901		14.811		14.952	-0.266			14.571
density functional	B3LYP	15.901		15.810		15.871	15.835			15.782
	PBEPBE									15.693
Moller Plesset perturbation	MP2	15.199		15.178		15.222	15.176			15.686

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.