III.G.1.a.

Comparison of levels of theory for Li-Li

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	2.3078 1
	PM3	2.5609 2
	PM6	1.9691 4
composite	G2	2.3354 4
	G3	2.3354 4
	G3B3	2.2403 4
	CBS-Q	2.3354 4

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	2.2225 4	2.2966 4	2.2966 4	2.3451 4	2.3359 4	2.3359 4	2.3206 4	2.3067 4	2.3067 4	2.3335 4	2.7852 1	2.3900 5	3.0938 3	3.2152 2	3.0683 3	3.2264 2	3.0676 3	3.0669 3
hartree fock	ROHF					3.1969 2
density functional	LSDA	1.9164 3	1.9281 3	1.9281 3	1.9467 3	1.9393 3	1.9393 3	1.9209 3	1.9039 3	1.9039 3	1.3585 2			2.8789 2	2.8421 2	2.9811 1	2.8672 2	2.9855 1	2.9786 1
	SVWN		2.2713 4			2.4389 4		2.2798 4
	BLYP	1.9477 3	1.9315 3	1.9315 3	1.9579 3	1.9481 3	1.9481 3	1.9161 3	1.9228 3	1.9228 3	1.9600 3			3.0479 1	3.0222 1		2.7164 1
	B1B95	2.2051 4	2.2320 4	2.2320 4	2.2668 4	2.2569 4	2.2571 4	2.2381 4	2.2314 4	2.2314 4	2.2486 4			2.9832 3	2.8864 2	3.0750 2	2.8941 2	3.0424 1	3.0653 2
	B3LYP	2.2097 4	2.2163 4	2.2163 4	2.2536 4	2.2403 4	2.2403 4	2.2215 4	2.2155 4	2.0524 3	2.2359 4	2.7009 1	2.3715 5	2.9562 3	3.0573 2	2.9281 3	3.0639 2	2.9329 3	2.9261 3
	B3LYPultrafine					2.2404 4
	B3PW91	1.5516 2	1.9693 3	1.9693 3	1.9862 3	1.9790 3	1.9790 3	1.9621 3	1.9527 3	1.5607 2	1.9779 3			3.1333 1	3.0996 1		2.7515 1
	mPW1PW91	2.0465 3	2.2460 4	2.0730 3	2.2792 4	2.2672 4	2.2672 4	2.2554 4	2.2442 4	2.2443 4	2.2584 4			3.1252 2	3.1021 2		2.7502 1
	M06-2X					2.3258 4
	PBEPBE	2.0517 3	2.2324 4	2.0587 3	2.1019 3	2.2535 4	2.2535 4	2.2394 4	2.2324 4	2.2324 4	2.2456 4	2.7276 1		2.9787 3	2.9602 3	3.0642 2			3.0612 2
	PBEPBEultrafine					2.7507 1
	HSEh1PBE					2.3138 4
Moller Plesset perturbation	MP2FC	2.0483 3	2.2792 4	2.2792 4	2.3247 4	2.3044 4	2.3044 4	2.2934 4	2.2753 4	2.2753 4	2.2994 4		2.3841 5	3.0575 3	3.1609 2	3.0207 3	3.0514 3	3.0239 3	3.0206 3
	MP2FU	2.0460 3	2.2771 4	2.1057 3	2.1601 3	2.2979 4	2.2979 4	2.2866 4	2.2683 4	2.1119 3	2.0873 3			3.1836 2	2.9937 3	2.9279 3	2.7624 1		3.0578 2
	MP3					1.9942 3
	MP4		2.0911 3			2.2773 4			2.7123 1	2.0960 3					2.9930 3
	B2PLYP					2.3106 4		2.2921 4
Configuration interaction	CID		1.5827 2	1.5827 2	1.6081 2	1.9728 3			1.9454 3
Configuration interaction	CISD				1.5983 2	1.3668 2
Quadratic configuration interaction	QCISD		2.2384 4	2.0718 3	2.1275 3	2.2641 4	2.1076 3	2.2550 4	2.2327 4	2.2327 4	2.1004 3			2.9973 3	2.9706 3
Quadratic configuration interaction	QCISD(T)					1.9606 3			2.6928 1					3.0979 1	3.0662 1		3.0870 1	3.0620 1
Coupled Cluster	CCD		2.0861 3	2.0861 3	2.1342 3	2.2715 4	2.1180 3	2.1093 3	2.2441 4	3.1417 2	2.1139 3			3.0128 3	3.1287 2		3.1540 2	3.1317 2
	CCSD					1.9648 3			2.6928 1
	CCSD(T)		2.7379 1			1.9621 3	2.7334 1	2.7384 1	2.6928 1	2.6928 1		2.7047 1		2.9154 2	2.8852 2	3.0655 1	2.9090 2	2.8828 2	3.0601 1
	CCSD(T)=FULL					2.0555 3										2.9838 2			2.9907 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	2.4223 4	3.2207 3	2.3342 4	3.0923 3	2.3269 4	2.3240 4
density functional	B1B95	2.9525 1	2.9539 1
density functional	B3LYP	2.4042 4	3.1946 3	2.2790 4	3.0148 3	2.2328 4	2.2343 4
Moller Plesset perturbation	MP2FC	2.4158 4	3.1937 3	2.3127 4	3.0482 3	2.3082 4	2.3012 4

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.