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 NH₂OH (hydroxylamine)

Experimental Ionization Energy is 10 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	9.199
	G3	9.169
	G3B3	9.211
	G4	9.203
	CBS-Q	9.176

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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-pVDZ	daug-cc-pVTZ
hartree fock	HF	6.532	8.298	8.298	8.400	8.206	8.151	8.302	8.227	8.191	8.072	8.227	8.272	8.103	8.158	8.185	8.257	8.217	8.206	8.251	8.214
density functional	BLYP		8.513	8.513	8.843	8.812	8.793	9.171	8.942	8.931	8.743	9.169	9.119	8.709	9.010		9.164	9.172		9.166	9.170
	B1B95	6.956	8.742	8.742	8.968	8.917	8.917	9.143	8.993	8.976	8.838	9.125	9.098	8.821	9.013		9.128	9.120			9.334
	B3LYP		8.827	8.827	9.099	9.047	9.017	9.329	9.150	9.133	8.964	9.315	9.287	8.941	9.185	9.251	9.313	9.313	9.304	9.314	9.311
	B3LYPultrafine		8.827			9.047	9.017	9.329	9.150		8.964	9.315	9.287	8.941	9.185		9.313	9.314		9.314	9.311
	B3PW91		8.847	8.847	9.077	9.017	8.984	9.242	9.104	9.085	8.932	9.223	9.197	8.924	9.111		9.226	9.213		9.225	9.210
	mPW1PW91		8.654	8.654	8.860	8.789	8.755	9.013	8.863	8.849	8.703	8.988	8.962	8.701	8.871		9.000	8.979		8.999	8.976
	M06-2X		9.029	9.029	9.205	9.158	9.114	9.352	9.269	9.242	9.067	9.175	9.357	9.054	9.292		9.331	9.383		9.330	9.379
	PBEPBE		8.592	8.592	8.874	8.838	8.812	9.147	8.943	8.930	8.769	9.142	9.093	8.746	8.996		9.145	9.144		9.145	9.142
	PBEPBEultrafine		8.592			8.838	8.812	9.147	8.943		8.769	9.142	9.093	8.746	8.996		9.145	9.145		9.145	9.142
	PBE1PBE		8.793	8.793	9.008	8.939	8.939	9.161	9.012	8.992	8.850	9.138	9.117	8.843	9.023		9.148	9.134		9.146	9.132
	HSEh1PBE		8.786	8.786	9.005	8.937	8.901	9.164	9.014	8.994	8.846	9.140	9.122	8.838	9.026		9.147	9.136		9.146	9.133
	TPSSh		8.590	8.590	8.798	8.716	8.684	8.949	8.804	8.782	8.630	8.928	8.905	8.620	8.812	8.871	8.931	8.924	8.922	8.930	8.923
	wB97X-D	7.074	8.851	8.851	9.094	9.048	9.017	9.272	9.121	9.101	8.961	9.233	9.190	8.953	9.108	9.153	9.245	9.202	9.194	9.243	9.197
	B97D3		8.711	8.711	8.961	8.904	8.877	9.182	8.996	8.981	8.829	9.165	9.119	8.818	9.022	9.089	9.178	9.155	9.149	9.176	8.961
		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-pVDZ	daug-cc-pVTZ
Moller Plesset perturbation	MP2		8.342	8.342	8.693	8.722	8.779	9.074	8.730	8.857	8.864	9.210	9.024	8.700	9.107	9.243	9.172	9.283	9.317	9.174	9.283
	MP2=FULL		8.342	8.342	8.694	8.719	8.777	9.071	8.728	8.855	8.859	9.200	9.024	8.700	9.083	9.239	9.171	9.262	9.310	9.173	9.261
	MP3					8.718		8.659				9.141	8.978	8.708	9.060
	MP3=FULL		8.386	8.386	8.676	8.714	8.773	9.019	8.718	8.841	8.857	9.130	8.977	8.707	9.034		9.113	9.181
	MP4		8.352			8.685				8.838		9.199	9.003	8.684	9.089		9.167	9.271
	MP4=FULL		8.352			8.681				8.834		9.188		8.683	9.063		9.166	9.248
	B2PLYP		8.657	8.657	8.960	8.931	8.925	9.228	8.999	9.023	8.915	9.263	9.183	8.851	9.136		9.252	9.282		9.253	9.281
	B2PLYP=FULL		8.657	8.657	8.960	8.930	8.924	9.228	8.998	9.022	8.915	9.260	9.183	8.851	9.130		9.252	9.278		9.253	9.276
	B2PLYP=FULLultrafine		8.656	8.656	8.960	8.728	8.925	9.228	8.998	9.022	8.915	9.260	9.183	8.654	8.933		9.252	9.081		9.253	9.276
Configuration interaction	CID		8.341	8.341	8.601	8.589			8.595			8.909		8.558	8.835
	CISD		8.270	8.270	8.544	8.547			8.559			8.881		8.519	8.804
		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-pVDZ	daug-cc-pVTZ
Quadratic configuration interaction	QCISD		8.223	8.223	8.557	8.619	8.671	8.939	8.642	8.751	8.758	9.062	8.895	8.611	8.965		9.035	9.119
	QCISD(T)					8.638			8.659			9.124	8.936	8.636	9.019		9.095	9.191		9.095	9.184
	QCISD(T)=FULL					8.635		8.973				9.113		8.635	8.994	9.145	9.093	9.170	9.196	9.094	9.164
	QCISD(TQ)					8.652		8.985				9.125		8.648			9.099
	QCISD(TQ)=FULL					8.648		8.982				9.115		8.647	8.999		9.097
Coupled Cluster	CCD		8.409	8.409	8.700	8.731	8.781	9.031	8.741	8.852	8.859	9.141	8.988	8.714	9.058		9.115	9.200
	CCSD					8.643	8.695	8.957	8.661	8.770	8.778	9.074	8.913	8.632	8.982	9.094	9.047	9.132		9.047
	CCSD=FULL					8.640					8.774	9.064	8.912	8.631	8.958	9.089	9.046	9.112
	CCSD(T)					8.642	8.702	8.978	8.663	8.784	8.800	9.126	8.939	8.640	9.023	9.142	9.096	9.193		9.096	9.186
	CCSD(T)=FULL					8.639						9.116	8.938	8.639		9.149	9.094	9.172	9.217	9.095	9.167
		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-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	8.436	8.283	8.453	8.288	8.446	8.448			8.190
density functional	BLYP									9.086
	B1B95									9.064
	B3LYP	9.207	9.171	9.250	9.211	9.195	9.190			9.247
	B3LYPultrafine									9.247
	B3PW91									9.158
	mPW1PW91									8.921
	M06-2X									9.309
	PBEPBE									9.063
	PBEPBEultrafine									9.063
	PBE1PBE									9.076
	HSEh1PBE									9.081
	TPSSh									8.866
	wB97X-D	9.140	9.105	9.191	9.145	9.149	9.146			9.158
	B97D3									9.086
Moller Plesset perturbation	MP2	8.859	8.914	8.934	8.963	8.868	8.873			9.173
	MP2=FULL									9.173
	MP3									9.114
	MP3=FULL									9.113
	MP4									9.155
	MP4=FULL									9.153
	B2PLYP									9.201
	B2PLYP=FULL									9.201
	B2PLYP=FULLultrafine									9.201
Configuration interaction	CID									8.883
	CISD									8.854
Quadratic configuration interaction	QCISD									9.023
	QCISD(T)									9.082
	QCISD(T)=FULL									9.080
	QCISD(TQ)									9.085
Coupled Cluster	CCD									9.113
	CCSD									9.039
	CCSD=FULL									9.038
	CCSD(T)									9.085
	CCSD(T)=FULL									9.084

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.