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
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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 SiF₂ (Silicon difluoride)

Experimental Ionization Energy is 10.78 ± 0.05 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

composite	G2	10.911
	G3	10.937
	G3B3	10.935
	G4	10.894
	CBS-Q	10.841

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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	aug-cc-pVDZ	aug-cc-pVTZ	daug-cc-pVTZ
hartree fock	HF	6.512	10.192	9.655	10.802	9.659	9.659	9.850	9.821	9.821	9.487		9.825	10.044	9.620	9.955	9.641	9.633
	ROHF		10.247	9.694	10.871	9.695	9.695	9.885	9.858	9.858				10.088	9.653	9.993	9.673
density functional	LSDA	7.364		10.893	11.765	11.078	11.078	11.450	11.318	11.318	11.025			11.347	11.256	11.533	11.316
	BLYP	6.623	10.400	10.162	10.997	10.353	10.353	10.777	10.591	10.591	10.308		10.726	10.594	10.549	10.847	10.645
	B1B95	7.102		10.383	11.310	10.524	10.524	10.833	10.727	10.727	10.442		10.796	10.834	10.618	10.928	10.668
	B3LYP	7.044	10.765	10.470	11.367	10.616	10.616	10.975	10.837	10.837	10.543		10.938	10.897	10.759	11.057	10.828
	B3LYPultrafine		10.764			10.617	10.617	10.975	10.837				10.938	10.896	10.759	11.057	10.828
	B3PW91	7.121	10.746	10.418	11.349	10.553	10.553	10.861	10.766	10.766	10.462		10.830	10.850	10.656	10.944	10.702
	mPW1PW91	7.131	10.752	10.411	11.357	10.535	10.535	10.837	10.738	10.738	10.437		10.797	10.836	10.619	10.922	10.669
	M06-2X	7.192	10.825	10.444	11.401	10.498	10.498	10.790	10.730	10.730	10.412	10.640	10.826	10.831	10.670	10.903	10.713
	PBEPBE	6.768	10.499	10.235	11.089	10.404	10.404	10.783	10.623	10.623	10.346		10.733	10.662	10.558	10.857	10.639
	PBEPBEultrafine		10.498			10.404	10.404	10.783	10.623				10.733	10.662	10.558	10.857	10.639
	PBE1PBE	7.055		10.390	11.319	10.507	10.507	10.814	10.708	10.708	10.416		10.778	10.810	10.599	10.899	10.652
	HSEh1PBE	7.053	10.716	10.387	11.319	10.511	10.511	10.823	10.715	10.714	10.419		10.790	10.810	10.608	10.906	10.660
	TPSSh		10.601	10.289	11.186	10.424	10.424	10.741	10.639				10.709	10.706	10.535	10.814	10.589
	wB97X-D	7.168	10.779	10.432	11.416	10.617	10.617	10.929	10.839	10.839	10.525		10.879	10.934	10.710	11.021	10.746
	B97D3											10.587						10.578
		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	6.213	10.162	9.892	10.835	10.178	10.178	10.538	10.316	10.316	10.239		10.465	10.447	10.439	10.690	10.558
	MP2=FULL	6.207	10.166	9.914	10.839	10.202	10.202	10.561	10.345	10.345	10.282		10.484	10.452	10.465	10.699	10.585
	MP3					10.402		10.052
	MP3=FULL					10.420		10.740
	MP4		10.210			10.354				10.490					10.635
	B2PLYP	6.718	10.540	10.252	11.159	10.436	10.436	10.793	10.622	10.622	10.406		10.739	10.716	10.609	10.899	10.697
	B2PLYP=FULL	6.716	10.541	10.259	11.160	10.443	10.443	10.799	10.631	10.631	10.418		10.744	10.717	10.616	10.902	10.705
	B2PLYP=FULLultrafine	6.715	10.540	10.259	11.160	10.443	10.443	10.799	10.631	10.631	10.418		10.744	10.717	10.616	10.902	10.705
Configuration interaction	CID		10.298	10.043	10.972	10.209			10.326
	CISD		10.252	10.000	10.917	10.183			10.304
		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	aug-cc-pVDZ	aug-cc-pVTZ	daug-cc-pVTZ
Quadratic configuration interaction	QCISD		10.251	10.087	10.922	10.368	10.368	10.723	10.516	10.516	10.447		10.657	10.665	10.630	10.880	10.730
	QCISD(T)					10.380			10.513				10.667	10.661	10.654	10.907	10.772
	QCISD(T)=FULL					10.392		10.757							10.665	10.911	10.782
Coupled Cluster	CCD		10.355	10.180	11.051	10.438	10.438	10.775	10.582	10.582	10.500		10.719	10.753	10.677	10.932	10.767
	CCSD					10.399					10.467		10.682	10.700	10.647	10.901	10.743
	CCSD=FULL					10.410					10.482		10.686	10.699	10.651	10.904	10.747
	CCSD(T)					10.391	10.391		10.524				10.678	10.675	10.662	10.915	10.778
	CCSD(T)=FULL					10.403							10.685		10.672	10.920	10.787
		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

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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	11.237	9.871	11.081	9.842	10.974	10.897			9.562
density functional	B3LYP	11.807	10.843	11.667	10.817	11.600	11.524			10.736
	PBEPBE									10.542
	wB97X-D	11.894	10.903	11.749	10.878	11.686	11.562
Moller Plesset perturbation	MP2	11.402	10.534	11.284	10.529	11.111	11.054			10.418

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.