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 Si (Silicon atom)

Experimental Ionization Energy is 8.15169 eV

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Ionization Energies in eV

Methods with predefined basis sets

semi-empirical	PM3
composite	G1	8.096
	G2MP2	8.031
	G2	8.098
	G3	8.127
	G3B3	8.129
	G3MP2	8.073
	G4	8.140
	CBS-Q	8.068

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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	daug-cc-pVTZ
hartree fock	HF	3.715	7.682	7.678	7.657	7.633	7.633	7.633	7.636	7.636	7.639	7.640	7.640	7.632	7.643	7.641	7.637	7.651	7.640	7.637	7.639
	ROHF	3.715	7.921	7.848	7.834	7.823	7.823	7.857	7.777	7.777	7.996	8.014	7.824	7.791	7.811	7.851	7.855	7.835	7.941	7.786
density functional	LSDA	4.962	6.973	8.700	8.666	8.658	8.658	8.673	8.671	8.671	8.665	8.670	8.670	8.675	8.666	8.675	8.670	8.684	8.678	8.670
	BLYP	4.253	7.958	7.957	7.942	7.927	7.927	7.952	7.936	7.936	7.934	7.942	7.942	7.942	7.931	7.935	7.941	7.963	7.947	7.943
	B1B95	4.521		8.085	8.045	8.037	8.037	8.048	8.032	8.032	8.040			8.037	8.040	8.031	8.038	8.054		8.039
	B3LYP	4.443	8.141	8.142	8.121	8.106	8.106	8.122	8.111	8.111	8.113	8.114	8.114	8.115	8.113	8.112	8.114	8.134	8.118	8.115
	B3LYPultrafine	4.443	8.141	8.142	8.121	8.106	8.106	8.122	8.111	8.111	8.113	8.114	8.114	8.115	8.113	8.112	8.114	8.134	8.118	8.115
	B3PW91	4.591	8.289	8.290	8.254	8.244	8.244	8.250	8.247	8.247	8.249	8.245	8.245	8.246	8.253	8.246	8.244	8.260	8.247	8.245
	mPW1PW91	4.573	8.276	8.276	8.248	8.237	8.237	8.244	8.240	8.240	8.242	8.241	8.241	8.238	8.242	8.237	8.241	8.252	8.240	8.243
	M06-2X	4.342	8.007	8.016	7.980	7.974	7.974	7.986	7.985	7.985	7.982	7.988	7.988	7.980	7.951	7.960	7.984	7.971	7.967	7.984
	PBEPBE	4.483	8.217	8.218	8.199	8.190	8.190	8.205	8.194	8.194	8.196	8.198	8.198	8.196	8.191	8.192	8.196	8.211	8.200	8.198
	PBEPBEultrafine	4.482	8.217	8.218	8.199	8.190	8.190	8.205	8.194	8.194	8.196	8.198	8.198	8.196	8.191	8.192	8.196	8.211	8.200	8.198
	PBE1PBE	4.516		8.253	8.227	8.216	8.216	8.224	8.219	8.219	8.222	8.220	8.220	8.219	8.221	8.218	8.219	8.231	8.221	8.220
	HSEh1PBE	4.509	8.244	8.245	8.216	8.204	8.204	8.212	8.208	8.208	8.210	8.208	8.208	8.207	8.211	8.206	8.207	8.221	8.208	8.208
	TPSSh					8.221		8.226			8.225					8.213
	wB97X-D			8.176		8.108		8.116		8.112				8.109	8.116	8.113			8.115
	B97D3		8.127			8.077		8.086		8.090		8.098		8.084		8.079			8.082
		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	daug-cc-pVTZ
Moller Plesset perturbation	MP2	3.503	7.592	7.830	7.569	7.791	7.791	7.792	7.801	7.801	8.017	8.032	8.032	7.871	7.920	8.042	8.070	7.962	8.051	8.076
	MP2=FULL	3.482	7.590	7.824	7.566	7.786	7.786	7.787	7.798	7.798	8.017	8.026	8.026	7.862	7.919	8.040	8.062	7.961	8.049	8.067
	ROMP2	3.914		9.026	8.223	8.974	8.974	9.029	8.978	8.978	9.519				9.117	9.492		9.199
	MP3	3.408	7.533	7.839	7.512	7.803	7.803	7.805	7.815	7.815	8.084	8.101	8.101	7.908	7.970	8.112	8.134	8.024	8.120	8.137
	MP3=FULL					7.795		7.796
	MP4	3.368	7.504	7.831	7.485	7.794	7.794	7.796	7.808	7.808	8.092	8.112	8.112	7.904	7.967	8.122	8.146	8.026	8.132	8.149
	MP4=FULL	3.348	7.502	7.822	7.482	7.786	7.786	7.788	7.801	7.801	8.086	8.098	8.098	7.891	7.963	8.114	8.131	8.022	8.124	8.134
Configuration interaction	CID	3.350	7.486	7.803	7.466	7.766	7.766	7.768	7.779	7.779	8.033	8.050	8.050	7.870	7.931	8.059	8.076	7.983	8.067	8.079
	CISD	3.350	7.486	7.804	7.467	7.766	7.766	7.768	7.780	7.780	8.030	8.047	8.047	7.869	7.929	8.057	8.073	7.980	8.063	8.076
		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	daug-cc-pVTZ
Quadratic configuration interaction	QCISD	3.350	7.487	7.811	7.468	7.772	7.772	7.775	7.787	7.787	8.042	8.060	8.060	7.878	7.939	8.070	8.087	7.991	8.077	8.089
	QCISD(T)	3.350	7.488	7.817	7.470	7.779	7.779	7.782	7.794	7.794	8.075	8.097	8.097	7.887	7.948	8.107	8.131	8.008	8.117	8.135
Coupled Cluster	CCD	3.350	7.488	7.809	7.467	7.772	7.772	7.774	7.785	7.785	8.044	8.062	8.062	7.878	7.940	8.071	8.089	7.993	8.079	8.091
	CCSD	3.350	7.487	7.810	7.468	7.772	7.772	7.775	7.786	7.786	8.043	8.060	8.060	7.878	7.939	8.070	8.087	7.991	8.077	8.090
	CCSD=FULL	3.331	7.485	7.804	7.465	7.767	7.767	7.768	7.784	7.784	8.040	8.052	8.052	7.866	7.935	8.064	8.076	7.988	8.071	8.079
	CCSD(T)	3.350	7.488	7.817	7.470	7.779	7.779	7.782	7.794	7.794	8.075	8.098	8.098	7.887	7.948	8.107	8.133	8.008	8.117	8.135
	CCSD(T)=FULL	3.330	7.486	7.810	7.467	7.773	7.773	7.775	7.788	7.788	8.071	8.087	8.087	7.875	7.945	8.100	8.119	8.004	8.110	8.123
		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	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	7.781	7.756	7.658	7.634	8.032	7.645			7.639
	ROHF	7.929	8.046	8.174	7.926	8.292	7.855
density functional	LSDA	8.669	8.667	8.539	8.537	8.916	8.649
	BLYP	8.034	8.023	7.898	7.888	8.281	7.905
	B1B95	8.081	8.074	7.942	7.935	8.341	8.024
	B3LYP	8.212	8.201	8.074	8.064	8.466	8.092			8.114
	B3LYPultrafine	8.212	8.201	8.074	8.064	8.466	8.092
	B3PW91	8.338	8.330	8.186	8.179	8.609	8.244
	mPW1PW91	8.336	8.327	8.186	8.178	8.600	8.233
	M06-2X	7.829	7.801	7.626	7.554	8.042	7.956
	PBEPBE	8.283	8.276	8.137	8.131	8.535	8.169			8.195
	PBEPBEultrafine	8.283	8.276	8.137	8.131	8.535	8.169
	PBE1PBE	8.314	8.305	8.167	8.159	8.575	8.209
	HSEh1PBE	8.308	8.298	8.161	8.152	8.568	8.198
Moller Plesset perturbation	MP2	7.653	7.991	7.557	7.889	7.880	7.552			8.043
	MP2=FULL	7.653	7.991	7.557	7.889	7.880	7.534
	MP3	7.584	8.028	7.498	7.931	7.802	7.493
	MP4	7.554	8.024	7.472	7.927	7.768	7.465
	MP4=FULL	7.554	8.024	7.472	7.927	7.768	7.448
Configuration interaction	CID	7.539	7.995	7.454	7.891	7.752	7.447
	CISD	7.541	7.994	7.456	7.890	7.753	7.447
Quadratic configuration interaction	QCISD	7.542	8.003	7.458	7.899	7.754	7.448
	QCISD(T)	7.543	8.010	7.460	7.910	7.754	7.449
Coupled Cluster	CCD	7.540	8.003	7.455	7.900	7.753	7.448
	CCSD	7.542	8.003	7.457	7.900	7.754	7.448
	CCSD=FULL	7.542	8.003	7.457	7.900	7.754	7.435
	CCSD(T)	7.543	8.011	7.460	7.910	7.754	7.449
	CCSD(T)=FULL	7.543	8.011	7.460	7.910	7.754	7.434

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.