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 Br₂ (Bromine diatomic)

Experimental Ionization Energy is 10.517 ± 0.003 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	AM1
	PM3
	PM6
composite	G2	10.668
	G3	10.707
	G3B3	10.708
	G3MP2	10.714
	G4	10.684
	CBS-Q	11.159

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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	8.387	10.627	9.993	10.973	10.209	10.209	10.270	10.282	10.282	10.065	10.111	10.233	10.305	10.105	10.083	10.277	10.100	10.084	10.271	10.099
density functional	LSDA	8.698	-3.666	10.649	11.263	10.882	10.882	10.982	11.025	11.025	10.834			10.970	10.949		11.025
	BLYP	7.878	10.040	9.818	10.411	10.073	10.073	10.217	10.246	10.248	10.027	10.191	10.228	10.160	10.176		10.259	10.179		10.256	10.178
	B1B95	7.752	-2.702	10.325	11.118	10.422	10.633	10.716	10.654	10.654	10.550	10.424	10.480	10.632	10.414		10.532	10.414			10.414
	B3LYP	8.402	10.531	10.227	10.891	10.468	10.468	10.580	10.608	10.610	10.404	10.530	10.581	10.556	10.519	10.506	10.615	10.518	10.506	10.612	10.517
	B3LYPultrafine		10.531			10.469	10.469	10.580	10.610		10.405	10.530	10.582	10.556	10.519		10.615	10.518		10.612	10.517
	B3PW91	8.533	10.666	10.321	10.991	10.526	10.526	10.600	10.619	10.621	10.453	10.528	10.590	10.624	10.521		10.635	10.516		10.628	10.515
	mPW1PW91	17.278	10.706	10.335	11.027	10.536	10.536	10.614	10.629	10.631	10.459	10.536	10.602	10.635	10.528		10.646	10.526		10.640	10.525
	M06-2X	8.735	10.871	10.417	11.355	10.794	10.794	10.871	10.882	10.882	10.705	10.779	10.789	10.897	10.734		10.893	10.733		10.887	10.732
	PBEPBE	8.101	10.272	10.000	10.613	10.227	10.227	10.337	10.358	10.361	10.171	10.292	10.336	10.318	10.277		10.373	10.280		10.368	10.279
	PBEPBEultrafine		10.273			10.228	10.228	10.338	10.361		10.172	10.292	10.336	10.318	10.277		10.373	10.280		10.368	10.279
	PBE1PBE	8.518	10.291	10.291	10.995	10.501	10.502	10.581	10.600	10.600	10.425	10.504	10.569	10.596	10.495		10.609	10.493		10.604	10.492
	HSEh1PBE	8.507	10.639	10.271	10.963	10.481	10.481	10.561	10.584	10.584	10.406	10.489	10.556	10.576	10.482		10.593	10.479		10.587	10.478
	TPSSh	8.367	10.580	10.239	10.870	10.419	10.420	10.495	10.525	10.525	10.350	10.438	10.498	10.520	10.432	10.417	10.530	10.431	10.420	10.523	10.431
	wB97X-D	8.634	10.812	10.379	11.113	10.572	10.572	10.645	10.630	10.630	10.490	10.522	10.608	10.666	10.520	10.508	10.672	10.515	10.509	10.665	10.514
	B97D3	8.236	10.247	9.991	10.593	10.215	10.215	10.323	10.357	10.357	10.154	10.288	10.339	10.315	10.280	10.269	10.373	10.279	10.272	10.368	10.279
		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	7.781	10.005	10.127	10.385	10.380	10.380	10.461	10.367	10.367	10.429	10.524	10.419	10.412	10.545	10.659	10.540	10.599	10.685	10.540	10.601
	MP2=FULL	7.779	10.002	10.122	10.373	10.382	10.382	10.463	10.392	10.392	10.440	10.558	10.398	10.408	10.526	10.634	10.537	10.573	10.659	10.536	10.573
	MP3					10.404		10.404				10.560	10.432	10.439	10.569					10.566	10.619
	MP3=FULL		10.081	10.139	10.464	10.401	10.401	10.479	10.395	10.395	10.469	10.567	10.411	10.434	10.547		10.561	10.589		10.560	10.587
	MP4		10.064			10.341				10.319		10.517	10.351	10.361	10.517		10.510	10.578		10.510	10.580
	MP4=FULL		10.060			10.335				10.323		10.528		10.356	10.498		10.506	10.554		10.506	10.554
	B2PLYP	8.203	10.337	10.165	10.705	10.410	10.411	10.509	10.490	10.490	10.379	10.485	10.486	10.475	10.480		10.555	10.500		10.553	10.499
	B2PLYP=FULL	8.202	10.336	10.163	10.701	10.411	10.411	10.509	10.497	10.497	10.382	10.494	10.480	10.474	10.475		10.554	10.492		10.552	10.491
	B2PLYP=FULLultrafine	8.202	10.336	10.163	10.701	10.411	10.411	10.510	10.497	10.497	10.382	10.494	10.480	10.474	10.475		10.554	10.492		10.552	10.491
Configuration interaction	CID		10.209	10.150	10.596	10.398			10.402			10.488		10.447	10.493					10.527	10.523
	CISD		10.188	10.132	10.576	10.379			10.383			10.467		10.428	10.474					10.509	10.505
		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		10.150	10.150	10.542	10.409	10.409	10.487	10.399	10.399	10.460	10.551	10.433	10.444	10.561		10.564	10.606		10.563	10.607
	QCISD(T)					10.349			10.333			10.518	10.367	10.375	10.520		10.519	10.579		10.519	10.580
	QCISD(T)=FULL					10.344		10.426				10.528		10.370	10.501	10.626	10.515	10.552	10.651	10.515	10.552
Coupled Cluster	CCD		10.176	10.179	10.567	10.439	10.439	10.516	10.430	10.430	10.496	10.590	10.467	10.476	10.601		10.595	10.646		10.594	10.647
	CCSD					10.415	10.415	10.493	10.405	10.405	10.465	10.557	10.439	10.450	10.567	10.681	10.569	10.610	10.703	10.568	10.611
	CCSD=FULL					10.410					10.466	10.569	10.421	10.446	10.546	10.657	10.565	10.583	10.678	10.564	10.582
	CCSD(T)					10.352	10.352	10.434	10.337	10.337	10.431	10.522	10.371	10.379	10.524	10.653	10.523	10.582	10.679	10.523	10.584
	CCSD(T)=FULL					10.347						10.532	10.352	10.374	10.504	10.630	10.519	10.555	10.654	10.518	10.555
		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	10.826		10.826		10.993	10.870	10.099		10.099
	ROHF							10.290
density functional	BLYP							10.118		10.167
	B1B95							10.371		10.409
	B3LYP	10.905		10.905		10.999	10.965	10.473		10.511
	B3LYPultrafine							10.473		10.511
	B3PW91							10.481		10.516
	mPW1PW91							10.487		10.524
	M06-2X							10.687		10.717
	PBEPBE							10.221		10.271
	PBEPBEultrafine							10.221		10.271
	PBE1PBE							10.452		10.490
	HSEh1PBE							10.441		10.477
	TPSSh							10.388		10.426
	wB97X-D	11.039		11.039		11.226	11.089	10.485		10.523
	B97D3							10.226		10.273
Moller Plesset perturbation	MP2	10.323		10.323		10.363	10.355	10.531		10.542
	MP2=FULL							10.518		10.517
	MP3							10.561		10.564
	MP3=FULL							10.544		10.537
	MP4							10.507		10.513
	MP4=FULL							10.494		10.491
	B2PLYP							10.447		10.475
	B2PLYP=FULL							10.443		10.467
	B2PLYP=FULLultrafine							10.443		10.467
Configuration interaction	CID							10.486		10.478
	CISD							10.468		10.462
Quadratic configuration interaction	QCISD							10.555		10.553
	QCISD(T)							10.513		10.515
	QCISD(T)=FULL							10.499		10.493
Coupled Cluster	CCD									10.594
	CCSD							10.560		10.558
	CCSD=FULL							10.545		10.536
	CCSD(T)							10.517		10.519
	CCSD(T)=FULL							10.503		10.496

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.