III.G.1.a.

Comparison of levels of theory for Cl-Si

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	1.9734 7
	PM3	2.0145 21
	PM6	2.0175 21
composite	G2	2.0464 17
	G3	2.0431 21
	G3B3	2.0621 21
	CBS-Q	2.0423 19

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
hartree fock	HF	2.0825 20	2.1590 21	2.0324 21	2.1664 21	2.0339 19	2.0432 21	2.0428 21	2.0408 21	2.0409 21	2.0396 21	2.0415 13	2.0528 21	2.0626 21	2.0429 21	2.0412 14	2.0666 21	2.0425 21	2.0324 10	2.0363 21
hartree fock	ROHF		2.2424 1	2.0764 1		2.0898 1	2.0898 1	2.0902 1	2.0900 1					2.1136 1	2.0866 1
density functional	LSDA	2.0905 21	2.1134 21	2.0266 21	2.1574 21	2.0416 21	2.0417 21	2.0413 21	2.0366 21	2.0368 21	2.0311 21			2.0583 21	2.0354 21	2.0017 5	2.0594 21	2.0071 5	1.9993 5
	SVWN		2.1446 21			2.0396 20		2.0412 21
	BLYP	2.1263 20	2.1939 21	2.0668 21	2.2065 21	2.0838 21	2.0841 21	2.0846 21	2.0822 21	2.0824 21	2.0745 21			2.1011 21	2.0792 21		2.1092 13
	B1B95	2.0938 21	2.1026 21	2.0297 21	2.1611 21	2.0413 21	2.0428 21	2.0423 21	2.0391 21	2.0394 21	2.0368 21			2.0602 21	2.0389 21	2.0070 5	2.0612 21	2.0256 8	2.0048 5
	B3LYP	2.1087 21	2.1713 21	2.0470 21	2.1830 21	2.0622 21	2.0624 21	2.0623 21	2.0596 21	2.0497 8	2.0541 21	2.0540 13	2.0691 21	2.0797 21	2.0568 21	2.0475 10	2.0856 17	2.0612 17	2.0461 10	2.0495 21
	B3LYPultrafine					2.0622 21		2.0891 4
	B3PW91	2.1016 8	2.1604 21	2.0382 21	2.1705 21	2.0512 21	2.0514 21	2.0509 21	2.0472 21	2.0360 8	2.0438 21			2.0687 21	2.0479 21		2.0785 13
	mPW1PW91	2.0872 9	2.1550 21	2.0265 10	2.1648 21	2.0461 21	2.0463 21	2.0458 21	2.0422 21	2.0425 21	2.0396 21			2.0635 21	2.0461 17		2.0738 13
	M06-2X					2.0449 21
	PBEPBE	2.1136 8	2.1742 21	2.0424 8	2.1819 8	2.0656 21	2.0658 21	2.0658 21	2.0627 21	2.0630 21	2.0572 21	2.0573 13		2.0833 18	2.0616 21	2.0285 5		2.0773 9	2.0259 5	2.0854 1
	PBEPBEultrafine					2.0717 13
	HSEh1PBE					2.0472 21
Moller Plesset perturbation	MP2FC	2.0964 8	2.1855 21	2.0260 21	2.1955 21	2.0383 21	2.0380 21	2.0374 21	2.0350 18	2.0337 21	2.0373 20		2.0482 21	2.0637 21	2.0444 17	2.0179 6	2.0820 14	2.0341 7	2.0299 5	2.0343 21
	MP2FU	2.0959 8	2.1931 17	2.0173 10	2.1914 10	2.0360 21	2.0357 21	2.0352 21	2.0330 21	2.0221 8	2.0173 8			2.0645 17	2.0236 8	2.0118 6	2.0996 6	1.9504 3	1.9986 5	2.0252 21
	MP3					2.0405 21
	MP4		2.1943 10			2.0485 17			2.0733 2	2.0315 8					2.0836 1
	B2PLYP					2.0508 21		2.0505 21
Configuration interaction	CID		2.1765 8	2.0192 10	2.1886 10	2.0383 21			2.0335 12
Configuration interaction	CISD		2.1795 8	2.0202 10	2.1913 10	2.0391 21			2.0274 10
Quadratic configuration interaction	QCISD		2.1946 21	2.0250 10	2.2042 10	2.0443 21	2.0368 10	2.0470 12	2.0434 17	2.0382 18	2.0196 5			2.0757 14	2.0462 8					2.0743 1
Quadratic configuration interaction	QCISD(T)					2.0497 9			2.0751 2					2.1579 2	2.1224 2		2.1691 2	2.1182 2
Coupled Cluster	CCD		2.1852 10	2.0219 10	2.1963 10	2.0416 21	2.0336 10	2.0279 8	2.0363 12	2.0155 5	2.0170 5			2.0723 14	2.0206 5		2.0553 5	2.0194 5
	CCSD					2.0420 18			2.0719 2
	CCSD(T)		2.2657 1			2.0527 13	2.0781 4	2.0832 1	2.0744 2	2.0823 1		2.0741 1		2.1420 3	2.1009 5		2.1676 2	2.1073 3		2.0761 1
	CCSD(T)=FULL					2.1178 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	2.1751 21	2.0567 21	2.1765 21	2.0570 21	2.1433 21	2.1598 21
density functional	B1B95	2.1949 13	2.0749 12
density functional	B3LYP	2.2029 21	2.0782 21	2.2008 21	2.0780 21	2.1688 21	2.1804 21
Moller Plesset perturbation	MP2FC	2.2068 21	2.0580 21	2.2072 21	2.0563 21	2.1673 21	2.1844 21

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.