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 S₃ (Sulfur trimer)

Experimental Ionization Energy is 9.68 ± 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

composite	G2	9.604
	G3	9.597
	G3B3	9.600
	G4	9.613
	CBS-Q	9.582

---

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	aug-cc-pV(T+d)Z	cc-pCVTZ	daug-cc-pVTZ
hartree fock	HF	5.734		9.407	9.610	9.354	9.354	9.338	9.331	9.331	9.068		9.202	9.157	9.042	9.058	9.110	9.056	9.046	9.037	9.050	9.037	9.053
density functional	LSDA	6.206	-0.307	10.201	10.283	10.154	10.155	10.173	10.175	10.175	9.979			9.991	10.014		10.019
	BLYP	5.395	9.405	9.310	9.411	9.290	9.290	9.341	9.356	9.355	9.142		9.256	9.128	9.180			9.212
	B1B95	6.027	0.064	9.760	10.061	9.718	9.718	9.723	9.732	9.655	9.446		9.560	9.562			9.553			9.511	9.529	9.519
	B3LYP	5.874		9.701		9.665	9.665	9.693	9.699	9.699	9.498		9.604	9.504	9.518	9.553	9.548	9.541	9.544			9.542
	B3LYPultrafine					9.664	9.664	9.692	9.699				9.603	9.504	9.518		9.548	9.540
	B3PW91	6.015		9.824		9.751	9.751	9.747	9.739	9.738	9.558		9.655	9.613	9.558
	mPW1PW91	6.163	10.044	9.831	9.994	9.759	9.759	9.759	9.753	9.752	9.559		9.660	9.618	9.557		9.597	9.569
	M06-2X	6.197	10.186		10.202						9.702	9.746	9.798	9.713	9.706		9.719	9.721
	PBEPBE	5.615	9.647	9.548	9.633	9.507	9.507	9.530	9.536	9.535	9.330		9.433	9.352	9.343		9.376	9.368		9.358	9.383	9.348
	PBEPBEultrafine		9.647			9.506	9.506	9.529	9.535				9.433	9.351	9.343		9.375	9.368
	PBE1PBE		9.804	9.804	9.976	9.743	9.742	9.743	9.738	9.738	9.540		9.640	9.590	9.536		9.573	9.550
	HSEh1PBE		10.003	9.788	9.954	9.723	9.723	9.725	9.723	9.723	9.526		9.627	9.573	9.525		9.561	9.539
	TPSSh		9.849		9.809	9.646	9.646	9.645	9.652				9.554	9.503	9.442		9.479	9.453
	wB97X-D			9.984		9.888		9.888		9.901				11.650	9.624			9.633
	B97D3		9.581			9.418		9.443		9.453		9.341	9.362		9.285			9.307					9.304
		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	aug-cc-pV(T+d)Z	cc-pCVTZ	daug-cc-pVTZ
Moller Plesset perturbation	MP2	5.106	9.823	9.236	9.816	9.241	9.241	9.260	9.258	9.258	9.467		9.228	9.213	9.485	9.774	9.446	9.570	9.648	9.499		9.504
	MP2=FULL	5.096	9.827	9.232	9.818	9.237	9.237	9.255	9.256	9.256	9.468		9.221	9.211	9.474	9.606	9.440	9.560	9.644	9.489		9.512
	MP3					9.334		9.189					9.305	9.299	9.557
	MP3=FULL					9.330		9.337					9.296	9.295	9.541
	MP4		9.616			9.160				9.176			9.139	9.119	9.432		9.358	9.527
	MP4=FULL		9.614			9.154				9.171				9.114	9.418		9.351	9.514
	B2PLYP	5.234	9.481	9.429	9.481	9.395	9.395	9.420	9.420	9.420	9.392		9.349	9.286	9.403		9.395	9.448
	B2PLYP=FULL	5.231	9.481	9.429	9.481	9.394	9.394	9.420	9.420	9.420	9.394		9.347	9.286	9.401		9.394	9.448
	B2PLYP=FULLultrafine					9.394								9.286	9.401			9.448
Configuration interaction	CID		9.757	9.413	9.777	9.379			9.379
	CISD		9.570	9.380	9.575	9.343			9.346
		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	aug-cc-pV(T+d)Z	cc-pCVTZ	daug-cc-pVTZ
Quadratic configuration interaction	QCISD			9.267		9.231	9.231	9.245	9.247	9.247	9.461		9.203	9.185	9.475		9.352	9.544		9.486
	QCISD(T)					9.107							9.075	9.058	9.374		9.260	9.462
	QCISD(T)=FULL					9.105		9.123						9.057	9.368	9.517	9.256	9.459	9.551
	QCISD(TQ)					9.088		9.106						9.045	9.362		9.246
	QCISD(TQ)=FULL					9.086								9.045
Coupled Cluster	CCD		9.745	9.396	9.779	9.380	9.380	9.390	9.390	9.390	9.584		9.349	9.334	9.601		9.511	9.671		9.607	9.678	9.611
	CCSD					9.265					9.485		9.237	9.220	9.500	9.625	9.387	9.569	9.652
	CCSD=FULL					9.264					9.487		9.232	9.219	9.493	9.622	9.383	9.564
	CCSD(T)					9.136							9.106	9.087	9.399	9.543	9.290	9.487	9.577	9.411	9.501	9.416
	CCSD(T)=FULL					9.134							9.098	9.086	9.391	9.539	9.285	9.481	9.573	9.403	9.495	9.423
		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	aug-cc-pV(T+d)Z	cc-pCVTZ	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	9.601	9.236	9.550	9.189	6.442				9.028
density functional	B3LYP	9.924	9.589	10.020	9.537	9.998
	PBEPBE									9.343
Moller Plesset perturbation	MP2	9.834	9.285	9.818	9.267	9.864	9.744			9.494

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.