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 OH (Hydroxyl radical)

Experimental Ionization Energy is 13.017 ± 0.0002 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

semi-empirical	PM3
composite	G2	12.937
	G3	12.895
	G3B3	12.901
	G3MP2	12.869
	G4	12.917
	CBS-Q	12.984

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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	cc-pV(T+d)Z	daug-cc-pVDZ	daug-cc-pVTZ
hartree fock	HF	8.559	10.850	10.850	11.243	11.213	12.074	11.330	11.221	11.218	11.221	11.342	11.257	11.131	11.265	11.295	11.336	11.316	11.312	11.265	11.322	11.310
	ROHF		10.947	10.947	11.388	11.319	11.319	11.597	11.337	11.438		11.579	11.476	11.240	11.369	11.533	11.556	11.552	11.549		11.423	11.409
density functional	LSDA		12.914	12.914	13.521	13.545	13.559	13.866	13.677	16.696	16.553			13.448	13.789	13.860	13.876	13.905	13.907
	BLYP	9.967	12.170	12.170	12.766	12.777	12.789	13.135	12.891	12.897	12.769	13.184	13.073	12.666	13.022		13.140	13.168		13.022	13.137	13.163
	B1B95	9.981	12.187	12.187	12.695	12.673	12.707	12.945	12.962	12.788	12.714	12.961	12.865	12.620	12.827	12.885	12.924		12.922	12.827
	B3LYP	10.146	12.354	12.354	12.903	12.905	12.914	13.191	12.996	13.000	12.901	13.234	13.134	12.803	13.101	13.171	13.196	13.214	13.216	13.101	13.191	13.208
	B3LYPultrafine		12.354			12.905	12.914	13.191	12.996		12.901	13.234	13.134	12.803	13.101		13.196	13.214			13.191	13.208
	B3PW91	10.126	12.364	12.364	12.845	12.838	12.846	13.073	12.914	12.918	12.837	13.112	13.012	12.752	12.996		13.081	13.086		12.996	13.073	13.079
	mPW1PW91	10.077	12.292	12.311	12.776	12.750	12.757	12.983	12.816	12.836	12.765	13.033	12.936	12.664	12.900		13.010	13.009		12.900	13.002	13.004
	M06-2X	10.014	12.341	12.341	12.777	12.774	12.773	12.984	12.876	12.870	12.785	13.047	12.953	12.684	12.966		13.003	13.046			12.995	13.038
	PBEPBE	9.991	12.250	12.250	12.793	12.796	12.807	13.114	12.889	12.898	12.795	13.160	13.054	12.702	13.013	13.091	13.125	13.146	13.150	13.013	13.120	13.142
	PBEPBEultrafine		12.250			12.797	12.808	13.114	12.889		12.795	13.160	13.054	12.702	13.013		13.125	13.147			13.120	13.142
	PBE1PBE	9.991	12.249	12.249	12.731	12.723	12.864	12.960	12.788	12.793	12.724	12.996	12.903	12.637	12.882		12.970	12.978			12.962	12.973
	HSEh1PBE	9.985	15.666	12.258	12.732	12.725	12.733	13.156	12.794	12.799	12.725	13.001	12.911	12.636	13.081		12.970	12.984			12.963	12.979
	TPSSh	9.934	12.177	12.177	12.644	12.610	12.607	12.841	12.693	12.680	12.599	12.879	12.793	12.513	12.767	12.829	12.850	12.864	12.873		12.841	12.859
	wB97X-D	10.072	12.381	12.381	12.835	12.835	12.843	13.057	12.888	12.889	12.828	13.069	12.954	13.057	12.929	12.986	13.056	13.010	13.021		13.045	13.003
	B97D3	10.021	12.209	12.209	12.683	12.683	12.693	12.961	12.759	12.766	12.684	12.999	12.897	12.599	12.853	12.934	12.977	12.971	12.987		12.969	12.969
		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	cc-pV(T+d)Z	daug-cc-pVDZ	daug-cc-pVTZ
Moller Plesset perturbation	MP2	8.697	11.550	11.550	12.154	12.352	12.408	12.617	12.365	12.435	12.614	12.904	12.536	12.269	12.778	12.951	12.719	12.924	13.009	12.778	12.710	12.918
	MP2=FULL	8.697	11.552	11.552	12.156	12.357	12.414	12.623	12.374	12.445	12.622	12.915	12.543	12.274	12.791	12.966	12.724	12.941	13.024	12.791	12.715	12.934
	ROMP2	8.726	11.578	11.578	12.186	12.371	12.425	12.633	12.379	12.448	12.623	12.911	12.549	12.282	12.785		12.732				12.723	12.925
	MP3					12.280		12.566				12.799	12.427	12.198	12.685						12.619	12.810
	MP3=FULL		11.524	11.524	12.114	12.283	12.343	12.534	12.281	12.350	12.563	12.810	12.432	12.202	12.696		12.632	12.832			12.623	12.825
	MP4		11.537			12.268				12.368		12.865	12.469	12.192	12.733		12.667	12.889			12.660	12.884
	MP4=FULL		11.537			12.272				12.376		12.877		12.196	12.746		12.671	12.905			12.664	12.900
	B2PLYP	9.620	12.026	12.026	12.587	12.641	12.663	12.913	12.701	12.725	12.719	13.030	12.849	12.545	12.899		12.950	13.023			12.944	13.017
	B2PLYP=FULL	9.621	12.026	12.026	12.588	12.642	12.665	12.914	12.703	12.728	12.721	13.033	12.851	12.546	12.903		12.952	13.028			12.946	13.022
	B2PLYP=FULLultrafine	9.620	12.026	12.026	12.588	12.642	12.665	12.914	12.703	12.728	12.721	13.033	12.850	12.546	12.903		12.952	13.028			12.946	13.022
Configuration interaction	CID		11.495	11.495	12.066	12.188			12.194			12.671		12.108	12.562						12.501	12.678
	CISD			11.486	12.055	12.179			12.192			12.676		12.100	12.562						12.506	12.683
		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	cc-pV(T+d)Z	daug-cc-pVDZ	daug-cc-pVTZ
Quadratic configuration interaction	QCISD		11.518	11.518	12.104	12.245	12.301	12.510	12.262	12.322	12.518	12.782	12.416	12.165	12.658		12.611	12.797		12.658	12.602	12.792
	QCISD(T)					12.252			12.285			12.845	12.454	12.178	12.712		12.649	12.867		12.712	12.642	12.862
	QCISD(T)=FULL					12.256		12.535				12.856		12.182	12.725	12.905	12.653	12.884	12.961		12.646	12.878
	QCISD(TQ)					12.258		12.532				12.840		12.182	12.709	12.885	12.648	12.861	12.940		12.640	12.856
	QCISD(TQ)=FULL					12.261		12.536				12.851		12.186	12.722	12.900	12.652	12.878			12.644	12.872
Coupled Cluster	CCD		11.526	11.526	12.114	12.254	12.309	12.502	12.263	12.324	12.525	12.770	12.408	12.174	12.656		12.597	12.786		12.656	12.588	12.780
	CCSD					12.245	12.300	12.504	12.260	12.321	12.518	12.776	12.412	12.165	12.655	12.816	12.603	12.791	12.865		12.594	12.786
	CCSD=FULL					12.248					12.525	12.787	12.417	12.170	12.668	12.831	12.607	12.808	12.880		12.598	12.801
	CCSD(T)					12.252	12.313	12.529	12.284	12.350	12.551	12.842	12.451	12.178	12.710	12.887	12.647	12.864	12.944	12.710	12.639	12.859
	CCSD(T)=FULL					12.256						12.854	12.457	12.182	12.723	12.903	12.650	12.881	12.959		12.643	12.875
		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	cc-pV(T+d)Z	daug-cc-pVDZ	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	11.270	11.208	11.229	11.190	11.226	11.223			11.291
	ROHF									11.393
density functional	BLYP									13.101
	B1B95									12.894
	B3LYP	12.920	12.877	12.904	12.891	12.981	12.970			13.163
	B3LYPultrafine									13.163
	B3PW91									13.041
	mPW1PW91									12.966
	M06-2X									12.978
	PBEPBE									13.083
	PBEPBEultrafine									13.083
	PBE1PBE									12.933
	HSEh1PBE									12.941
	TPSSh									12.818
	wB97X-D	12.816	12.787	12.810	12.803	12.826	12.817			12.985
	B97D3									12.926
Moller Plesset perturbation	MP2	12.177	12.357	12.221	12.400	12.194	12.196			12.825
	MP2=FULL									12.833
	ROMP2									12.832
	MP3									12.728
	MP3=FULL									12.735
	MP4									12.780
	MP4=FULL									12.787
	B2PLYP									12.956
	B2PLYP=FULL									12.958
	B2PLYP=FULLultrafine									12.958
Configuration interaction	CID									12.603
	CISD									12.605
Quadratic configuration interaction	QCISD									12.704
	QCISD(T)									12.760
	QCISD(T)=FULL									12.768
	QCISD(TQ)									12.757
	QCISD(TQ)=FULL									12.765
Coupled Cluster	CCD									12.699
	CCSD									12.700
	CCSD=FULL									12.708
	CCSD(T)									12.758
	CCSD(T)=FULL									12.765

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.