III.G.1.a.

Comparison of levels of theory for Br-Br

Click on an entry for a histogram of the values.
The subscript refers to how many bonds of that type have been calculated.

average calculated bond lengths (Å)

Methods with predefined basis sets
semi-empirical	AM1	2.2282 2
	PM3	2.4801 3
	PM6	2.3821 3
composite	G2	2.4555 3
composite	CBS-Q	2.5345 2

average calculated bond lengths (Å)

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
hartree fock	HF	2.5019 2	2.5846 3	2.4291 3	2.5618 3	2.4555 3	2.4555 3	2.4578 3	2.4672 3	2.5564 2	2.4320 3	2.2722 1	2.4702 3	2.4683 3	2.4525 3	2.2726 1	2.4729 3	2.4514 3	2.2726 1
hartree fock	ROHF					2.8912 1
density functional	LSDA	2.4732 3	2.4664 3	2.4045 3	2.5663 3	2.4429 3	2.4429 3	2.4396 3	2.5797 2	2.5797 2	2.4144 3			2.4602 3	2.4351 3		2.4539 3	2.5097 2
	SVWN		2.5860 3			2.5601 2		2.4398 3
	BLYP	2.6258 2	2.6931 3	2.5067 3	2.6622 3	2.5559 3	2.5559 3	2.6894 2	2.5761 3	2.6798 2	2.5185 3			2.7270 2	2.5560 3
	B1B95	2.4785 3	2.4941 3	2.4329 3	2.5847 3	2.4661 3	2.4672 3	2.4660 3	2.4820 3	2.4820 3	2.4401 3			2.4855 3	2.4624 3		2.4813 3	2.5484 2
	B3LYP	2.5012 3	2.6411 3	2.4678 3	2.6173 3	2.5076 3	2.5076 3	2.5055 3	2.5228 3	2.6174 2	2.4765 3		2.5245 3	2.5246 3	2.5045 3	2.3129 1	2.5211 3	2.5009 3	2.3130 1
	B3LYPultrafine					2.6012 2
	B3PW91	2.5700 2	2.6167 3	2.4411 3	2.5931 3	2.4765 3	2.4765 3	2.4744 3	2.4890 3	2.5795 2	2.4487 3			2.4931 3	2.4704 3
	mPW1PW91	2.4440 3	2.6044 3	2.4306 3	2.5819 3	2.4643 3	2.4643 3	2.4629 3	2.4766 3	2.5650 2	2.4378 3			2.4804 3	2.4584 3
	M06-2X					2.4498 3
	PBEPBE	2.5967 2	2.6447 3	2.4614 3	2.6212 3	2.6339 2	2.6339 2	2.4983 3	2.6555 2	2.9815 1	2.4716 3			2.5211 3	2.4974 3		2.3302 1	2.3114 1
	PBEPBEultrafine					2.3146 1
	HSEh1PBE					2.4673 3
Moller Plesset perturbation	MP2FC	2.5342 2	2.6430 3	2.4355 3	2.6297 3	2.4717 3	2.4717 3	2.4738 3	2.4728 3	2.5552 2	2.4301 3		2.4706 3	2.4788 3	2.2768 1	2.2613 1	2.4852 3	2.2787 1	2.2611 1
	MP2FU	2.5342 2	2.6431 3	2.4338 3	2.6294 3	2.4648 3	2.4648 3	2.4667 3	2.4681 3	2.5503 2	2.4177 3			2.4773 3	2.2326 2	2.2571 1	2.3241 1
	MP3					2.4837 3
	MP4		2.6531 3			2.4864 3				2.5742 2					2.4534 3
	B2PLYP					2.4874 3		2.4884 3
Configuration interaction	CID		2.6381 3	2.4373 3	2.6232 3	2.4726 3			2.4744 3
Configuration interaction	CISD		2.6415 3	2.4381 3	2.6271 3	2.4735 3			2.4764 3
Quadratic configuration interaction	QCISD		2.6498 3	2.4457 3	2.6367 3	2.4825 3	2.4825 3	2.4867 3	2.4864 3	2.5677 2	2.4438 3			2.4902 3	2.4493 3
Quadratic configuration interaction	QCISD(T)					2.4876 3								2.5747 2	2.2133 1		2.5865 2	2.5293 2
Coupled Cluster	CCD		2.6457 3	2.4441 3	2.6318 3	2.4807 3	2.4807 3	2.4846 3	2.4828 3	2.5639 2	2.4415 3			2.4877 3	2.1952 1		2.5761 2	2.5202 2
	CCSD					2.4824 3
	CCSD(T)					2.3340 1								2.4968 3	2.2574 2		2.5072 3	2.4539 3
	CCSD(T)=FULL					2.5567 2

average calculated bond lengths (Å)

Methods with effective core potentials (select basis sets)
		CEP-31G	CEP-31G*	CEP-121G	CEP-121G*	LANL2DZ	SDD
hartree fock	HF	2.5564 3		2.5564 3		2.6058 3	2.5624 3
density functional	B1B95	2.4281 1
density functional	B3LYP	2.6218 3		2.6218 3		2.6733 3	2.6257 3
Moller Plesset perturbation	MP2FC	2.6359 3		2.6359 3		2.6759 3	2.6357 3

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.