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 P₂ (Phosphorus diatomic)

Experimental Ionization Energy is 10.53 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	PM3
composite	G2	10.539
	G3	10.546
	G3B3	10.556
	G4	10.806
	CBS-Q	10.531

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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-pVTZ
hartree fock	HF	5.897	9.708	9.477	9.598	9.396	9.396	9.398	9.413	9.413	9.205		9.309	9.272	9.199	9.199	9.262	9.207	9.202	9.205
density functional	LSDA	8.047	5.847	11.245	11.218	11.145	11.145	11.168	11.209	11.209	11.051			11.069	11.103		11.094	11.105
	BLYP	7.029	10.324	10.239	10.236	10.160	10.160	10.206	10.243	10.243	10.071			10.074	10.117
	B1B95	7.389		10.508	10.510	10.389	10.416	10.431	10.449	10.449	10.298			10.335	10.287		10.320	10.297
	B3LYP	7.234	10.584	10.468	10.482	10.384	10.384	10.414	10.445	10.445	10.278		10.366	10.295	10.313	10.316	10.333	10.325	10.321
	B3LYPultrafine					10.384												10.763
	B3PW91	7.400	10.734	10.599	10.597	10.490	10.490	10.497	10.520	10.520	10.365			10.412	10.388
	mPW1PW91	7.369	10.694	10.577	10.588	10.445	10.445	10.455	10.477	10.504	10.341			10.360	10.333
	M06-2X			10.537		10.477						10.387
	PBEPBE	7.316	10.612	10.505	10.503	10.417	10.417	10.442	10.469	10.469	10.306			10.330	10.334
	PBE1PBE					10.839
	HSEh1PBE		10.917					10.836							10.735
	TPSSh					10.456		10.465			10.327				10.352
	wB97X-D			10.612		10.480		10.489		10.504			10.434	10.489	10.368			10.372
	B97D3		10.527			10.308		10.335		10.357		10.258	10.283		10.230			10.239		10.236
		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-pVTZ
Moller Plesset perturbation	MP2	6.665	10.272	10.399	10.256	10.339	10.339	10.360	10.382	10.382	10.533		10.359	10.367	10.578	10.672	10.494	10.633	10.701
	MP2=FULL	6.657	10.269	10.402	10.255	10.342	10.342	10.362	10.382	10.382	10.554			10.373	10.586	10.674			10.706
	MP3					10.015
	MP3=FULL					10.013		10.027
	MP4		10.141			10.173				10.223
	B2PLYP					10.339									10.361
	B2PLYP=FULLultrafine					10.340								10.289	10.364			10.394
Configuration interaction	CID		9.970	9.983	9.898	9.907			9.942
	CISD		9.967	9.989	9.897	9.911			9.948
		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-pVTZ
Quadratic configuration interaction	QCISD		10.055	10.121	10.004	10.049	10.049	10.064	10.088	10.088	10.216			10.054	10.251
	QCISD(T)					10.107								10.129	10.378		10.253	10.429
Coupled Cluster	CCD		10.056	10.105	10.000	10.035	10.035	10.049	10.070	10.070	10.205			10.041	10.242		10.146	10.287
	CCSD(T)					10.102								10.125	10.374		10.249	10.425
	CCSD(T)=FULL					10.102
		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-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	9.581	9.229	9.541	9.244	9.699	9.638			9.195
density functional	B3LYP	10.428	10.242	10.369	10.213	10.508	10.528			10.302
	PBEPBE									10.323
Moller Plesset perturbation	MP2	10.152	10.301	10.190	10.342	10.200	10.236			10.575

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.