III.G.1.a.

Comparison of levels of theory for B-B

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	1.2225 4
	PM3	1.4692 1
	PM6	1.4841 8
composite	G2	1.5716 10
	G3	1.5715 10
	G3B3	1.6389 10
	CBS-Q	1.5388 8

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	cc-pV(T+d)Z	cc-pCVDZ	cc-pCVTZ
hartree fock	HF	1.5159 9	1.5674 10	1.5690 10	1.5712 10	1.5602 9	1.5725 10	1.5744 10	1.5695 10	1.5617 9	1.5645 9	1.6843 4	1.5655 11	1.5787 10	1.5708 10	1.5118 7	1.5625 9	1.5700 10	1.5116 7	1.7046 1	1.6492 1	1.6364 1
hartree fock	ROHF	1.4469 1	1.5150 1	1.5150 1	1.5157 1	1.5704 2	1.5058 1	1.5080 1	1.5038 1	1.5038 1	1.5034 1			1.5150 1	1.5028 1		1.5149 1	1.5024 1
density functional	LSDA	1.5394 8	1.5639 8	1.5660 8	1.5698 8	1.5745 8	1.5745 8	1.5765 8	1.5648 8	1.5647 8	1.5710 8			1.5796 8	1.5665 8		1.5786 8	1.4825 4
	SVWN		1.5341 8			1.5831 6		1.5377 8
	BLYP	1.5842 9	1.6134 10	1.6078 9	1.6607 10	1.6172 10	1.6177 10	1.6184 10	1.6018 9	1.6088 9	1.6132 9			1.6223 10	1.6084 10		1.6817 3
	B1B95	1.5147 10	1.6389 10	1.6406 10	1.5965 10	1.5819 10	1.5820 10	1.6013 10	1.6347 10	1.6346 10	1.6384 10			1.5866 10	1.5911 10	1.5418 4	1.5728 10	1.5718 5	1.5911 3		1.6288 1	1.6155 1
	B3LYP	1.5854 10	1.6369 10	1.6386 10	1.6412 10	1.6394 10	1.6394 10	1.6402 10	1.6337 10	1.6152 6	1.6392 9	1.6789 3	1.6694 11	1.6445 10	1.6321 10	1.6111 7	1.6289 8	1.6152 8	1.6110 7	1.6838 1	1.6280 1	1.6121 1
	B3LYPultrafine					1.6419 9		1.6935 1
	B3PW91	1.5068 6	1.6388 10	1.6405 10	1.6417 10	1.6410 10	1.6403 10	1.6032 9	1.6352 10	1.6169 6	1.6416 9			1.6451 10	1.6345 10		1.6815 3
	mPW1PW91	1.4895 7	1.6382 10	1.6328 7	1.6415 10	1.5973 10	1.5973 10	1.5991 10	1.5920 10	1.5893 9	1.6409 9			1.6022 10	1.5640 8		1.6324 5	1.5430 2
	M06-2X	1.4367 1	1.4669 1	1.4669 1	1.4725 1	1.5289 9	1.4666 1	1.4682 1	1.4627 1	1.4630 1	1.4635 1			1.4795 1	1.4602 1		1.4764 1	1.4600 1
	PBEPBE	1.5369 6	1.6131 10	1.5961 7	1.5968 7	1.6173 10	1.6173 10	1.6175 10	1.5979 9	1.6084 9	1.6137 9	1.6803 3		1.6208 10	1.6092 10	1.5855 4	1.5114 4	1.5403 6	1.5853 4
	PBEPBEultrafine					1.6707 4
	HSEh1PBE	1.4365 1	1.4678 1	1.4678 1	1.4713 1	1.6610 8	1.4645 1	1.4657 1	1.4617 1	1.4618 1	1.4627 1			1.4778 1	1.4592 1		1.4745 1	1.4590 1
Moller Plesset perturbation	MP2FC	1.4757 6	1.5750 10	1.5764 10	1.5817 10	1.5719 10	1.5718 10	1.5747 10	1.5741 10	1.5713 9	1.5490 8		1.5703 11	1.5899 10	1.5582 9	1.5169 7	1.6062 8	1.5222 7	1.5175 7	1.6901 1	1.6187 1	1.5972 1
	MP2FU	1.4754 6	1.5478 8	1.5387 7	1.5421 7	1.5693 10	1.5363 8	1.5384 8	1.5719 10	1.5142 6	1.5049 6			1.5577 8	1.5125 7	1.5101 7	1.5638 6	1.5134 5	1.4979 6	1.6756 1	1.6169 1	1.5934 1
	ROMP2	1.4827 1	1.5424 1	1.5424 1	1.5453 1	1.5234 1	1.5234 1	1.5255 1	1.5281 1	1.5281 1	1.5217 1			1.5446 1	1.5217 1		1.5449 1
	MP3					1.5693 9
	MP4		1.6366 7			1.5650 9				1.5279 6					1.5756 7
	B2PLYP	1.4390 1	1.4694 1	1.4694 1	1.4741 1	1.5298 9	1.4634 1	1.5317 9	1.4619 1	1.4629 1	1.4611 1			1.4814 1	1.4384 1		1.4784 1	1.4999 1
Configuration interaction	CID		1.7198 6	1.7198 6	1.5685 6	1.6038 7			1.6030 6
Configuration interaction	CISD		1.5927 5	1.5927 5	1.5963 5	1.5981 6			1.5812 5
Quadratic configuration interaction	QCISD		1.7075 9	1.7280 6	1.5541 7	1.5776 10	1.5320 7	1.5537 6	1.5900 8	1.5840 7	1.5422 5			1.5779 6	1.5515 6		1.5841 2	1.5592 2
Quadratic configuration interaction	QCISD(T)					1.5825 8			1.7219 1					1.5851 6	1.5848 5		1.6730 4	1.5998 3
Coupled Cluster	CCD		1.6082 7	1.6082 7	1.5490 7	1.5665 9	1.5272 7	1.5297 7	1.5570 8	1.5213 6	1.5152 6			1.5521 7	1.5379 5		1.6627 6	1.5384 5			1.6278 1	1.6015 1
	CCSD					1.5603 7								1.5853 2	1.5592 2
	CCSD(T)					1.5823 8	1.7188 1		1.7220 1			1.4886 1		1.5902 7	1.5865 6	1.6085 6	1.6430 6	1.6125 7	1.6009 5		1.6255 1	1.5979 1
	CCSD(T)=FULL					1.5991 5								1.5988 3	1.5508 4	1.6000 6	1.5839 2	1.5493 2	1.5918 5		1.6236 1	1.5939 1

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	1.6145 10	1.6100 10	1.5859 10	1.5788 10	1.5823 10	1.5811 10
density functional	B1B95	1.7023 4	1.7087 4
density functional	B3LYP	1.7338 9	1.6650 9	1.7019 10	1.6574 10	1.6565 10	1.6572 10
Moller Plesset perturbation	MP2FC	1.7351 10	1.6180 10	1.6781 10	1.5799 10	1.6000 10	1.5988 10

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.