National Institute of Standards and Technology

Computational Chemistry Comparison and Benchmark DataBase
Release 22	May 2022
NIST Standard Reference Database 101

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XVI	Bibliographic data
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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 AlH₂ (aluminum dihydride)

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	7.115
	G3	7.211
	G4	7.215
	CBS-Q	7.141

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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	3.460	6.616	6.734	6.646	6.743	6.728	6.742	6.757	6.743	6.776		6.754	6.756	6.789	6.803	6.765	6.788	6.803	6.790
	ROHF		6.606	6.714		6.722	6.706	6.720	6.735					6.730	6.760
density functional	LSDA	3.897	7.533	7.601	7.566	7.619	7.609	7.623	7.620	7.611	7.599			7.592	7.603		7.600
	BLYP		6.960	7.031	7.000	7.052	7.039	7.059	7.060	7.050	7.041			7.039	7.047
	B1B95	3.435		7.029	7.019	7.063	7.044	7.058	7.105	7.045	7.041			7.035	7.045		7.048
	B3LYP	3.632	7.112	7.189	7.152	7.208	7.194	7.211	7.213	7.201	7.199		7.204	7.194	7.204	7.222	7.205	7.200	7.222
	B3LYPultrafine					7.207												7.199
	B3PW91		7.180	7.244	7.216	7.258	7.249	7.261	7.251	7.240	7.247			7.237	7.246
	mPW1PW91	4.025	7.149	7.232	7.207	7.231	7.220	7.234	7.221	7.228	7.239			7.209	7.220
	M06-2X			7.110		7.193						7.188
	PBEPBE		7.122	7.184	7.157	7.195	7.185	7.201	7.189	7.178	7.182			7.180	7.182
	PBE1PBE					7.213
	HSEh1PBE		7.132			7.213		7.215							7.204
	TPSSh					7.236		7.240			7.225				7.220
	wB97X-D			7.078		7.084		7.088		7.081			7.078	7.088	7.084			7.082
	B97D3		6.982			7.080		7.092		7.070		7.088	7.068		7.073			7.075		7.079
		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		6.620	6.783	6.647	6.792	6.823	6.839	6.806	6.865	6.929		6.874	6.896	6.982		6.934	6.993
	MP2=FULL	2.655	6.617			6.793	6.825	6.842	6.809	6.868				6.898
	MP3					6.812
	MP3=FULL					6.813		6.868
	MP4		6.622			6.825
	B2PLYP					6.999									7.061
	B2PLYP=FULLultrafine					6.999								7.024	7.055			7.042
Configuration interaction	CID					6.814			6.823
	CISD					6.822
		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		6.618	40.585		6.828	6.859	6.875	6.839	6.901				6.947	7.033
	QCISD(T)					6.839								6.960	7.054
Coupled Cluster	CCD		6.615			6.818	6.853	6.868	6.828					6.939	7.020
	CCSD					6.826
	CCSD(T)													6.960	7.054
		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	6.595	6.724	6.630	6.790	6.711	6.675			6.800
density functional	B3LYP	7.105	7.160	7.128	7.196	7.209	7.145			7.227
	PBEPBE									7.204
Moller Plesset perturbation	MP2	6.600	6.791	6.634	6.849	6.715	6.671			6.994

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.