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 CCl₃ (Trichloromethyl radical)

Experimental Ionization Energy is 8.109 ± 0.005 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	PM3
composite	G2	7.990
	G4	8.133
	CBS-Q	8.114

---

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	aug-cc-pVDZ	aug-cc-pVTZ	daug-cc-pVTZ
hartree fock	HF	8.273	9.275	8.504	9.101	8.267	8.267	8.283	8.273	8.273	8.056		8.302	8.212	8.060	8.215	8.072	8.068
	ROHF		9.183	8.386		8.139	8.139	8.156	8.145					8.086	7.917
density functional	LSDA	7.698	8.821	8.378	8.683	8.276		8.360	8.404	8.404	8.203			8.253	8.286
	BLYP	7.310	8.386	7.842	8.236	7.762	7.762	7.879	7.918	7.918	7.680			7.734	7.767
	B1B95	7.778		8.117	8.500	7.962	7.962	8.018	8.030	8.030	7.848			7.939	7.883	7.996
	B3LYP	7.834	8.819	8.261	8.674	8.147	8.147	8.229	8.258	8.258	8.038		8.233	8.114	8.100	8.213	8.127
	B3LYPultrafine					8.147											8.127
	B3PW91	7.915	8.862	8.325	8.688	8.178	8.178	8.222	8.234	8.234	8.067			8.164	8.100
	mPW1PW91	7.980	8.857	8.366	8.740	8.163	8.163	8.211	8.216	8.265	8.097			8.145	8.076
	M06-2X			8.371		8.227						8.118
	PBEPBE	7.400	8.463			7.857	7.857	7.942	7.967	7.966	7.777				7.835
	PBE1PBE					8.172
	HSEh1PBE		8.845			8.162		8.213							8.083
	TPSSh					8.105		8.153			8.002				8.038
	wB97X-D			8.415		8.241		8.280		8.286			8.287	8.280	8.126		8.132
	B97D3		8.570			7.878		7.955		7.982		7.846	7.960		7.847		7.875	7.873
		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	aug-cc-pVDZ	aug-cc-pVTZ	daug-cc-pVTZ
Moller Plesset perturbation	MP2	6.921	8.361	7.839	8.210	7.659	7.659	7.733	7.712	7.712			7.772	7.718		7.939
	MP2=FULL		8.357			7.646	7.646	7.719	7.699	7.699				7.706
	MP3					7.894
	MP3=FULL					7.884		7.950
	MP4					7.612
	B2PLYP					7.941									7.965
	B2PLYP=FULLultrafine					7.938								7.935	7.956		8.000
Configuration interaction	CID					7.993
	CISD					7.973
		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	aug-cc-pVDZ	aug-cc-pVTZ	daug-cc-pVTZ
Quadratic configuration interaction	QCISD		8.513			7.835
Coupled Cluster	CCD					7.910
	CCSD					7.869
	CCSD(T)					7.729
		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	aug-cc-pVDZ	aug-cc-pVTZ	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	9.127	8.293	9.129	8.306	9.355	9.209			8.028
density functional	B3LYP	8.801	8.267	8.782	8.260	8.844	8.731			8.069
	PBEPBE									7.810
Moller Plesset perturbation	MP2	8.255	7.813	8.254	7.839	8.329	8.222			7.805

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.