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 HN₃ (hydrogen azide)

Experimental Ionization Energy is 10.56 ± 0.02 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	10.719
	G3	10.700
	G3B3	10.701
	G4	10.683
	CBS-Q	10.735

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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		8.281	8.281	8.588	8.775	8.780	8.850	8.752	8.761	8.760	8.860	8.769	8.707	8.797	8.824	8.848	8.838	8.838	8.828	8.834
	ROHF		8.425	8.425	8.918	9.107	9.113	9.177	9.072	9.079		9.188	9.073	9.035	9.123	9.150	9.188	9.164	9.165	9.169	9.159
density functional	BLYP	8.578	10.188	10.188	10.481	10.468	10.474	10.669	10.551	10.559	10.439	10.685	10.650	10.381	10.588		10.656	10.672		10.654	10.669
	B1B95	8.599	10.276	10.276	10.519	10.549	10.549	10.668	10.570	10.578	10.521		10.621	10.476	10.594		10.655	10.648			10.644
	B3LYP	8.616	10.314	10.314	10.599	10.606	10.611	10.765	10.664	10.672	10.574	10.777	10.737	10.522	10.695	10.738	10.753	10.762	10.763	10.747	10.758
	B3LYPultrafine		10.314			10.606	10.611	10.765	10.664		10.574	10.777	10.737	10.522	10.695		10.753	10.762		10.747	10.758
	B3PW91	8.702	10.439	10.439	10.643	10.653	10.658	10.764	10.687	10.695	10.609	10.762	10.723	10.579	10.695		10.746	10.743		10.732	10.739
	mPW1PW91	8.607	10.370	10.370	10.569	10.583	10.587	10.697	10.609	10.617	10.538	10.692	10.653	10.511	10.621		10.681	10.674		10.668	10.672
	M06-2X	8.443	10.290	10.290	10.565	10.644	10.647	10.759	10.691	10.697	10.620	10.793	10.719	10.561	10.745		10.750	10.794		10.739	10.789
	PBEPBE	8.766	10.420	10.420	10.639	10.630	10.634	10.790	10.685	10.693	10.594	10.795	10.766	10.556	10.713		10.777	10.786		10.769	10.783
	PBEPBEultrafine		10.420			10.630	10.634	10.790	10.685		10.594	10.795	10.766	10.556	10.713		10.777	10.786		10.769	10.783
	PBE1PBE	8.559	10.335	10.335	10.545	10.559	10.559	10.675	10.584	10.592	10.519	10.673	10.637	10.489	10.605		10.662	10.660		10.649	10.657
	HSEh1PBE	8.551	10.333	10.333	10.540	10.553	10.557	10.671	10.582	10.591	10.511	10.669	10.637	10.479	10.603		10.655	10.657		10.643	10.654
	TPSSh	8.579	10.298	10.298	10.506	10.506	10.509	10.619	10.535	10.540	10.448	10.608	10.585	10.424	10.545	10.580	10.591	10.600	10.604	10.578	10.598
	wB97X-D	8.491	10.343	10.343	10.558	10.596	10.601	10.704	10.610	10.618	10.550	10.686	10.627	10.514	10.597	10.635	10.682	10.643		10.666	10.638
	B97D3	8.770	10.408	10.408	10.599	10.588	10.593	10.728	10.628	10.636	10.538	10.720	10.696	10.516	10.637	10.683	10.709	10.704	10.710	10.696	10.702
		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	8.215	10.221	10.221	10.978	11.112	11.143	11.307	11.099	11.140	11.295	11.506	11.158	11.051	11.391	11.535	11.430	11.530		11.421
	MP2=FULL	8.216	10.223	10.223	10.980	11.118	11.149	11.314	11.109	11.150	11.298	11.518	11.165	11.056	11.400	11.545	11.435	11.538		11.426	11.536
	ROMP2	6.638	9.625	9.625	10.105	10.444	10.478	10.638	10.476	10.524	10.682	10.910	10.573	10.400	10.798		10.757			10.747	10.933
	MP3					10.322		10.229
	MP3=FULL					10.328		10.483
	MP4		10.037			10.762				10.833					11.098
	B2PLYP	8.220	10.142	10.142	10.527	10.573	10.585	10.740	10.611	10.629	10.617	10.821	10.689	10.500	10.728		10.769	10.817		10.761
	B2PLYP=FULL	8.221	10.142	10.142	10.528	10.575	10.588	10.743	10.614	10.633	10.620	10.826	10.692	10.502	10.733		10.771	10.823		10.763	10.820
	B2PLYP=FULLultrafine	8.221	10.142	10.142	10.528	10.575	10.588	10.743	10.614	10.633	10.620	10.826	10.692	10.502	10.733		10.771	10.823		10.763
Configuration interaction	CID		9.287	9.287	9.871	10.023			10.002			10.311		9.968	10.229					10.229
	CISD		9.217	9.217	9.712	9.939			9.933			10.249		9.884	10.167					10.139	10.255
		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		9.210	9.210	9.663	10.006	10.032	10.162	10.028	10.063	10.254	10.433	10.085	9.955	10.336		10.270	10.448		10.259	10.446
	QCISD(T)					10.138			10.170			10.608	10.241	10.090	10.499		10.436	10.630		10.428	10.628
	QCISD(T)=FULL					10.146		10.317				10.630		10.096	10.523		10.442	10.656	10.716	10.433
Coupled Cluster	CCD		9.469	9.469	10.126	10.318	10.347	10.481	10.302	10.340	10.528	10.690	10.343	10.264	10.591		10.598	10.707		10.588	10.705
	CCSD					10.003	10.030	10.161	10.022	10.059	10.253	10.431	10.080	9.954	10.333		10.273	10.446
	CCSD=FULL					10.011					10.267	10.454	10.090	9.961	10.360	10.490	10.280	10.475		10.269	10.473
	CCSD(T)					10.150	10.179	10.322	10.183	10.222	10.417	10.623	10.254	10.102	10.514	10.657	10.451	10.646	10.710	10.441	10.644
	CCSD(T)=FULL					10.157							10.262	10.108	10.538	10.684	10.456	10.672		10.447	10.666
		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	8.383	8.640	8.424	8.713	8.493	8.493			8.825
	ROHF									9.149
density functional	BLYP									10.644
	B1B95									10.633
	B3LYP	10.524	10.493	10.519	10.527	10.658	10.647			10.740
	B3LYPultrafine									10.740
	B3PW91									10.725
	mPW1PW91									10.656
	M06-2X									10.741
	PBEPBE									10.759
	PBEPBEultrafine									10.759
	PBE1PBE									10.640
	HSEh1PBE									10.639
	TPSSh									10.579
	wB97X-D	10.411	10.419	10.417	10.456	10.531	10.523			10.640
	B97D3									10.684
Moller Plesset perturbation	MP2	11.159	11.219		11.135	11.143	11.147			11.445
	MP2=FULL									11.449
	ROMP2									10.857
	B2PLYP									10.777
	B2PLYP=FULL									10.780
	B2PLYP=FULLultrafine									10.780
Configuration interaction	CID									10.267
	CISD									10.205
Quadratic configuration interaction	QCISD									10.382
	QCISD(T)									10.549
	QCISD(T)=FULL									10.560
Coupled Cluster	CCD									10.637
	CCSD									10.379
	CCSD=FULL									10.392
	CCSD(T)									10.563
	CCSD(T)=FULL									10.577

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.