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

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IV.D.4. (XII.A.2.)

Comparison of experiment and theory for rHI

Species with coordinate rHI

Species	Name
HI	Hydrogen iodide

The small prefix is the number of bonds with completed calculations.
Click on an entry for a histogram of the difference distribution.

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rms differences (calculated - experiment) in Å

Methods with predefined basis sets

semi-empirical	PM3	1 0.068

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rms differences (calculated - experiment) in Å

Methods with standard basis sets

		3-21G	3-21G*	6-31G*	6-311G*	6-311G**
hartree fock	HF	2 0.029	2 0.022		3 0.013	2 0.000
	ROHF				1 0.008
density functional	LSDA				1 0.037
	BLYP	2 0.068	2 0.051		3 0.044	2 0.030
	B1B95	1 0.044	2 0.030		3 0.022	2 0.009
	B3LYP	2 0.052	2 0.038		3 0.031	2 0.017
	B3LYPultrafine				1 0.030
	B3PW91	2 0.048	2 0.033		3 0.027	2 0.014
	mPW1PW91	2 0.045	2 0.031		3 0.024	2 0.011
	M06-2X		1 0.028		1 0.018
	PBEPBE	2 0.062	2 0.045		3 0.040	2 0.025
	PBEPBEultrafine				1 0.040
	PBE1PBE				1 0.025
	HSEh1PBE				1 0.026
	TPSSh				1 0.025
	wB97X-D		1 0.028		1 0.021
	B97D3	1 0.057			1 0.033
		3-21G	3-21G*	6-31G*	6-311G*	6-311G**
Moller Plesset perturbation	MP2	2 0.048	2 0.036	1 0.033	4 0.030	2 0.003
	MP2=FULL	2 0.048	2 0.036		3 0.028	2 0.002
	ROMP2				1 0.024
	MP3				1 0.031
	MP3=FULL				1 0.033
	MP4				1 0.036
	MP4=FULL				1 0.037
	B2PLYP				1 0.026
	B2PLYP=FULL				1 0.026
	B2PLYP=FULLultrafine				1 0.026
Configuration interaction	CID	2 0.061	2 0.042		3 0.030	2 0.003
	CISD	2 0.063	2 0.043		3 0.031	2 0.002
		3-21G	3-21G*	6-31G*	6-311G*	6-311G**
Quadratic configuration interaction	QCISD	2 0.065	2 0.047		3 0.039	2 0.003
	QCISD(T)	2 0.065	2 0.049		3 0.041	2 0.004
	QCISD(T)=FULL				1 0.041
Coupled Cluster	CCD	2 0.063	2 0.046		3 0.037	2 0.002
	CCSD				1 0.037
	CCSD=FULL				1 0.038
	CCSD(T)	2 0.065	2 0.049		3 0.041	2 0.004
	CCSD(T)=FULL				1 0.042
		3-21G	3-21G*	6-31G*	6-311G*	6-311G**

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rms differences (calculated - experiment) in Å

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	1 0.007		1 0.004		1 0.006	1 0.008	2 0.008		3 0.020
	ROHF							2 0.009		2 0.014
density functional	LSDA							2 0.019		2 0.013
	BLYP							2 0.026		2 0.020
	B1B95	1 0.032		1 0.030		1 0.029	1 0.032	2 0.004		2 0.002
	B3LYP	1 0.031		1 0.029		1 0.027	1 0.030	2 0.012		3 0.005
	B3LYPultrafine							2 0.012		2 0.007
	B3PW91							2 0.009		2 0.003
	mPW1PW91							2 0.006		2 0.000
	M06-2X							2 0.003		2 0.003
	PBEPBE							2 0.022		3 0.014
	PBEPBEultrafine							2 0.022		2 0.016
	PBE1PBE							2 0.007		2 0.002
	HSEh1PBE							2 0.009		2 0.003
	TPSSh							2 0.010		2 0.004
	wB97X-D							2 0.005		2 0.001
	B97D3							2 0.017		2 0.011
Moller Plesset perturbation	MP2	1 0.028		1 0.025		1 0.024	1 0.028	2 0.009		3 0.025
	MP2=FULL							2 0.011		2 0.023
	ROMP2							2 0.009		2 0.019
	MP3							2 0.005		2 0.014
	MP3=FULL							2 0.008		2 0.018
	MP4							2 0.002		2 0.010
	MP4=FULL							2 0.004		2 0.015
	B2PLYP							2 0.004		2 0.003
	B2PLYP=FULL							2 0.003		2 0.005
	B2PLYP=FULLultrafine							2 0.003		2 0.005
Configuration interaction	CID							2 0.007		2 0.021
	CISD							2 0.006		2 0.020
Quadratic configuration interaction	QCISD							2 0.002		2 0.011
	QCISD(T)							2 0.001		2 0.008
	QCISD(T)=FULL							2 0.002		2 0.013
Coupled Cluster	CCD							2 0.003		2 0.012
	CCSD							2 0.002		2 0.011
	CCSD=FULL							2 0.004		2 0.016
	CCSD(T)							2 0.001		2 0.008
	CCSD(T)=FULL							2 0.002		2 0.013

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.