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

---

NIST policy on privacy, security, and accessibility.

---

© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to cccbdb@nist.gov.

XVII.C.1. (III.D.6.)

Calculated Ionization Energy for HBr (hydrogen bromide)

Experimental Ionization Energy is 11.68 ± 0.03 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.

---

Ionization Energies in eV

Methods with predefined basis sets

semi-empirical	AM1
	PM3
	PM6
composite	G2	11.737
	G3	11.780
	G3B3	11.779
	G3MP2	11.777
	G4	11.771
	CBS-Q	11.824

---

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	8.731	10.639	10.509	10.920	10.681	10.695	10.752	10.692	10.703	10.653	10.669	10.687	10.702	10.658	10.654	10.749	10.659	10.658	10.741	10.659
	ROHF		10.659	10.621	10.940	10.789	10.803	10.847	10.808	10.819		10.813	10.805	10.812	10.801	10.800	10.861	10.804	10.802	10.854	10.803
density functional	LSDA	10.325	5.101	12.165	12.437	12.340	12.355	12.444	12.432	12.449	12.355			12.383	12.446		12.482
	BLYP	9.497	11.242	11.258	11.550	11.449	11.460	11.584	11.570	11.582	11.450	11.592	11.580	11.488	11.573		11.622	11.585		11.619	11.584
	B1B95	9.475	5.039	11.498	11.843	11.619	11.732	11.808	11.721	11.737	11.716	11.676	11.666	11.700	11.660		11.722			11.718	11.666
	B3LYP	9.768	11.505	11.498	11.800	11.679	11.692	11.790	11.768	11.780	11.680	11.782	11.774	11.715	11.768	11.768	11.818	11.773	11.771	11.816	11.774
	B3LYPultrafine		11.502			11.680	11.696	11.793	11.769		11.683	11.782	11.777	11.716	11.770		11.819	11.775		11.816	11.774
	B3PW91	9.864	11.582	11.560	11.848	11.714	11.728	11.795	11.762	11.775	11.712	11.770	11.769	11.753	11.758		11.820	11.762		11.814	11.762
	mPW1PW91	13.260	11.557	11.528	11.822	11.681	11.696	11.766	11.729	11.742	11.677	11.738	11.739	11.720	11.726		11.789	11.732		11.783	11.732
	M06-2X	9.821	11.503	11.418	11.818	11.673	11.688	11.759	11.674	11.689	11.661	11.691	11.663	11.682	11.660		11.744	11.665		11.737	11.665
	PBEPBE	9.684	11.415	11.412	11.696	11.585	11.597	11.695	11.670	11.682	11.581	11.689	11.679	11.624	11.669		11.725	11.681		11.721	11.680
	PBEPBEultrafine		11.409			11.585	11.601	11.698	11.670		11.586	11.689	11.679	11.625	11.671		11.724	11.680		11.721	11.680
	PBE1PBE	9.788	11.492	11.492	11.790	11.650	11.652	11.738	11.702	11.714	11.647	11.709	11.708	11.689	11.697		11.757	11.702		11.751	11.702
	HSEh1PBE	9.784	11.521	11.496	11.784	11.648	11.662	11.732	11.702	11.716	11.645	11.710	11.712	11.686	11.701		11.757	11.706		11.751	11.705
	TPSSh	9.785	11.552	11.514	11.800	11.659	11.673	11.739	11.718	11.727	11.653	11.721	11.719	11.698	11.708	11.706	11.760	11.715	11.710	11.754	11.715
	wB97X-D	9.847	11.592	11.551	11.825	11.682	11.697	11.763	11.699	11.715	11.689	11.710	11.726	-54.875	11.707	11.710	11.793	11.710	11.712	11.786	11.710
	B97D3	9.716	11.366	11.364	11.667	11.548	11.561	11.655	11.640	11.653	11.538	11.651	11.648	11.606	11.637	11.641	11.699	11.643	11.643	11.694	11.643
		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	8.751	10.856	11.195	11.169	11.387	11.435	11.501	11.333	11.392	11.552	11.647	11.475	11.431	11.688	11.824	11.604	11.748	11.853	11.601	11.749
	MP2=FULL	8.750	10.855	11.194	11.163	11.404	11.453	11.518	11.370	11.432	11.593	11.701	11.463	11.432	11.686	11.818	11.605	11.748	11.847	11.602	11.749
	MP3					11.355		11.403				11.615	11.401	11.375	11.625					11.551	11.681
	MP3=FULL		10.870	11.137	11.181	11.356	11.406	11.470	11.285	11.346	11.542	11.620	11.384	11.373	11.615		11.551	11.673		11.547	11.673
	MP4		10.872			11.332				11.337		11.629	11.402	11.355	11.649		11.554	11.714		11.551	11.715
	MP4=FULL		10.870			11.337				11.358		11.662		11.354	11.645		11.553	11.714		11.551	11.714
	B2PLYP	9.396	11.250	11.348	11.551	11.533	11.558	11.641	11.566	11.593	11.587	11.678	11.616	11.568	11.680		11.695	11.705		11.691	11.705
	B2PLYP=FULL	9.395	11.249	11.348	11.549	11.538	11.564	11.646	11.578	11.606	11.599	11.695	11.612	11.568	11.679		11.695	11.705		11.691	11.704
	B2PLYP=FULLultrafine	9.396	11.248	11.348	11.549	11.539	11.565	11.649	11.578	11.607	11.601	11.696	11.613	11.568	11.680		11.695	11.706		11.691	11.705
Configuration interaction	CID		10.860	11.060	11.176	11.266			11.210			11.477		11.286	11.477					11.435	11.521
	CISD		10.851	11.053	11.167	11.260			11.203			11.467		11.278	11.469					11.429	11.511
		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		10.862	11.103	11.181	11.312	11.357	11.421	11.252	11.307	11.479	11.558	11.364	11.332	11.578		11.508	11.628		11.505	11.629
	QCISD(T)					11.316			11.263			11.607	11.383	11.340	11.624		11.536	11.687		11.533	11.688
	QCISD(T)=FULL					11.321		11.436				11.631		11.338	11.619	11.761	11.534	11.684	11.788	11.532	11.685
Coupled Cluster	CCD		10.872	11.111	11.189	11.319	11.365	11.429	11.259	11.315	11.489	11.569	11.372	11.342	11.588		11.514	11.639		11.511	11.640
	CCSD					11.311	11.357	11.421	11.251	11.306	11.479	11.558	11.364	11.333	11.578	11.709	11.507	11.628	11.731	11.504	11.629
	CCSD=FULL					11.315					11.497	11.577	11.349	11.331	11.570	11.697	11.504	11.623	11.719	11.501	11.623
	CCSD(T)					11.316	11.364	11.430	11.263	11.322	11.519	11.608	11.383	11.340	11.625	11.771	11.535	11.687	11.797	11.533	11.688
	CCSD(T)=FULL					11.331						11.631	11.369	11.339	11.619	11.762	11.534	11.684	11.788	11.531	11.685
		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

---

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	10.845		10.833		10.882	10.905	10.647		10.660
	ROHF							10.785		10.803
density functional	LSDA							12.396
	BLYP							11.521		11.573
	B1B95							11.620		11.663
	B3LYP	11.790		11.786		11.789	11.864	11.726		11.768
	B3LYPultrafine							11.726		11.768
	B3PW91							11.719		11.761
	mPW1PW91							11.687		11.730
	M06-2X							11.607		11.666
	PBEPBE							11.617		11.671
	PBEPBEultrafine							11.617		11.671
	PBE1PBE							11.656		11.699
	HSEh1PBE							11.661		11.703
	TPSSh							11.667		11.709
	wB97X-D	11.773		11.764		11.837	11.828	11.674		11.717
	B97D3							11.588		11.637
Moller Plesset perturbation	MP2	11.088		11.075		11.079	11.129	11.681		11.697
	MP2=FULL							11.679		11.688
	ROMP2							11.658
	MP3							11.616		11.629
	MP3=FULL							11.608		11.615
	MP4							11.642		11.658
	MP4=FULL							11.639		11.649
	B2PLYP							11.652		11.684
	B2PLYP=FULL							11.652		11.680
	B2PLYP=FULLultrafine							11.652		11.681
Configuration interaction	CID							11.471		11.470
	CISD							11.463		11.462
Quadratic configuration interaction	QCISD							11.572		11.583
	QCISD(T)							11.619		11.632
	QCISD(T)=FULL							11.614		11.621
Coupled Cluster	CCD							11.581		11.593
	CCSD							11.572		11.583
	CCSD=FULL							11.565		11.570
	CCSD(T)							11.619		11.632
	CCSD(T)=FULL							11.614		11.621

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.