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 Ne₂ (Neon diatomic)

Experimental Ionization Energy is 20.33 ± 0.08 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.

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Ionization Energies in eV

Methods with predefined basis sets

composite	G2	20.306
	G3	20.304
	G3B3	20.295
	G4	20.203
	CBS-Q	20.319

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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	12.783				19.314	19.314	19.740	19.624	19.624	19.183		19.723	19.438	19.590	19.563	19.713	19.595	19.556	19.568
density functional	LSDA	10.531	16.937	16.937	18.377	18.295	18.295	19.271	18.898	18.898	18.246			18.408	19.044		19.234	19.219
	BLYP	9.953	16.147	16.147		17.486	17.486	18.588	18.063	18.063	17.428				18.265
	B1B95	11.406			18.578	18.487	18.487	19.296	18.958	18.958	18.410			18.601	19.067		19.271	19.203
	B3LYP	10.996	17.098	17.098	18.417	18.340	18.340	19.254	18.855	18.855	18.267		19.196	18.446	19.000	19.099	19.228	19.184	19.160
	B3LYPultrafine					18.337
	B3PW91	11.242	17.345	17.345		18.451	18.451	19.254	18.920	18.920	18.357			18.563	19.030
	mPW1PW91	11.362	17.414	17.414	18.601	18.513	18.513	19.302	18.963	18.963	18.422			18.621	19.066		19.280	19.206
	M06-2X	11.864	18.009	18.020	19.100	18.990	18.990	19.697	19.504	19.504	18.908	19.708		19.089	19.698		19.665	19.772
	PBEPBE	10.137	16.342	16.342	17.653	17.592	17.592	18.587	18.109	18.109	17.524			17.692	18.293		18.563	18.534
	HSEh1PBE	11.198	17.275	17.275	18.488	18.401	18.401		18.853	18.853	18.315			18.506	18.973		19.167	19.116
	TPSSh					18.015		18.847			17.926				18.623
	wB97X-D			17.636		18.660		19.403		19.096			19.291	19.403	19.125			19.220
	B97D3		16.905			17.950		18.827		18.407		18.770	18.714		18.543			18.749		18.737
		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		18.384	18.384	19.558	19.505	19.505	20.167	19.900	19.900	19.535		20.151	19.624	20.164	20.305	20.238	20.292	20.343
	MP2=FULL		18.385	18.385	19.559	19.505	19.505	20.166	19.907	19.907	19.534			19.626	20.168	20.320	20.238	20.285	20.355
	MP3					19.497
	MP3=FULL					19.496		20.065
	MP4		18.417			19.449				19.784					20.015
	B2PLYP=FULLultrafine					18.814								18.921	19.422			19.575
Configuration interaction	CID					19.494			19.867
	CISD					19.449			19.817
		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					19.454	19.454	20.050	19.810	19.810	19.466			19.567	20.035		20.109	20.127
	QCISD(T)					19.435								19.537	20.001
Coupled Cluster	CCD				19.603	19.512	19.512	20.092	19.881	19.881	19.535			19.637	20.108		20.166	20.190
	CCSD					19.455								19.573	20.041
	CCSD(T)					19.435								19.539	20.003	20.130	20.082	20.105	20.155
	CCSD(T)=FULL					19.434								19.540	20.005	20.144	20.081		20.165
		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	19.913		19.824		19.790	19.785			19.614
density functional	B3LYP	19.050		19.042		18.933	18.921			19.141
	PBEPBE									18.455
Moller Plesset perturbation	MP2	20.098		20.060		19.981	19.977			20.241

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.