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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III.F.2.

Completed calculations for C₄H₈Cl₂ (Butane, 2,3-dichloro-, (r*,r*)-(.+/-.)-)

Methods and basis sets for which an energy has been calculated. "e" indicates just an energy has been calculated. "o" indicates an optimized geometry. "v" indicates vibrational frequencies. "s" followed by a number indicates completed calculations for different states (for example s1ov). "c" followed by a number indicates completed calculations for different conformations (for example c2ov).
See the Calculated Energies page (section III.A.1) for more calculated properties.

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Methods with predefined basis sets

semi-empirical	PM3	o

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Methods with standard basis sets

		3-21G*	6-31G*	6-311+G(3df,2p)	TZVP	cc-pVDZ	cc-pVTZ	aug-cc-pVTZ	daug-cc-pVTZ
density functional	M06-2X	ov		ov
	PBEPBE			ov
	B97D3			ov	ov				ov
Moller Plesset perturbation	B2PLYP=FULLultrafine		ov			ov	o	o
		3-21G*	6-31G*	6-311+G(3df,2p)	TZVP	cc-pVDZ	cc-pVTZ	aug-cc-pVTZ	daug-cc-pVTZ

Barriers to internal rotation or inversion

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Methods with predefined basis sets

semi-empirical	AM1	s1c1t1
	PM3	s1c1t1

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Methods with standard basis sets

		3-21G	6-31G*	6-31+G**
hartree fock	HF	s1c1t1	s1c1t1	s1c1t1
density functional	B3LYP	s1c1t1	s1c1t1	s1c1t1
		3-21G	6-31G*	6-31+G**
Moller Plesset perturbation	MP2	s1c1t1	s1c1t1	s1c1t1
		3-21G	6-31G*	6-31+G**

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.