III.G.1.a.

Comparison of levels of theory for Na-Cl

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	PM6	2.5499 7
composite	G2	2.5910 7
	G3	2.5910 7
	G3B3	2.5742 3
	CBS-Q	2.5910 7

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	2.4043 7	2.6230 7	2.5880 7	2.6390 7	2.5909 7	2.5910 7	2.5721 7	2.5888 7	2.5887 7	2.5764 7	2.5295 5	2.6506 3	2.6022 7	2.7017 2	2.5930 3	2.7093 2	2.5832 7	2.5920 3	2.5995 3
density functional	LSDA	2.3424 7	2.5304 7	2.5032 7	2.5503 7	2.5092 7	2.5092 7	2.5151 7	2.5069 7	2.5069 7	2.4833 7			2.5206 7	2.5052 7	2.4586 1	2.5069 7	2.4653 1	2.5761 2
	SVWN		2.5438 7			2.4693 6		2.5151 7
	BLYP	2.3952 7	2.5942 7	2.5589 7	2.6164 7	2.5765 7	2.5765 7	2.5874 7	2.5852 7	2.5851 7	2.5577 7			2.7004 2	2.6878 2		2.5375 5
	B1B95	2.3895 7	2.5751 7	2.5476 7	2.6150 7	2.5560 7	2.5562 7	2.5634 7	2.5168 6	2.5168 6	2.4973 6			2.5710 7	2.5569 7		2.5948 4
	B3LYP	2.3866 7	2.5823 7	2.5461 7	2.6025 7	2.5633 7	2.5609 7	2.5695 7	2.5663 7	2.6802 2	2.5431 7	2.5092 5	2.5832 7	2.5694 7	2.6690 2	2.5641 3	2.6758 2	2.5598 7	2.5607 3	2.5723 3
	B3LYPultrafine					2.5635 7
	B3PW91	2.5869 2	2.6089 7	2.5738 7	2.6174 7	2.5713 7	2.5713 7	2.5766 7	2.5722 7	2.6940 2	2.5525 7			2.7199 2	2.6864 2		2.5243 5
	mPW1PW91	2.5803 2	2.5952 7	2.6882 2	2.6082 7	2.5622 7	2.5622 7	2.5677 7	2.5619 7	2.5619 7	2.5445 7			2.7050 2	2.6722 2		2.5175 5
	M06-2X					2.8286 7
	PBEPBE	2.5698 2	2.5929 7	2.6776 2	2.7506 2	2.5664 7	2.5664 7	2.5745 7	2.5691 7	2.5696 7	2.5470 7	2.5128 5		2.5759 7	2.5655 7	2.6594 2			2.6543 2
	PBEPBEultrafine					2.5220 5
	HSEh1PBE					2.5563 7
Moller Plesset perturbation	MP2FC	2.6033 2	2.6378 7	2.5726 7	2.6520 7	2.5586 7	2.5656 7	2.5686 7	2.5537 7	2.5541 7	2.6066 6		2.6117 7	2.6018 7	2.7006 2	2.5989 3	2.6272 3	2.6093 3	2.4075 1	2.6020 3
	MP2FU	2.5993 2	2.6382 7	2.6853 2	2.8134 2	2.5647 7	2.5628 7	2.5623 7	2.5443 7	2.6500 2	2.6606 2			2.7281 2	2.6687 2	2.5642 3	2.5465 5			2.5785 3
	MP3					2.5627 7
	MP4		2.7865 2			2.8635 7			2.3863 1	2.6550 2					2.4055 1
	B2PLYP					2.5557 7		2.5623 7
Configuration interaction	CID		2.7862 2	2.6884 2	2.8146 2	2.5667 7			2.5671 3
Configuration interaction	CISD		2.7863 2	2.6890 2	2.8148 2	2.5658 7			2.6592 2
Quadratic configuration interaction	QCISD		2.6398 7	2.6873 2	2.8157 2	2.5663 7	2.6709 2	2.5800 3	2.5528 7	2.5662 3	2.6861 2			2.6215 3	2.5999 3
Quadratic configuration interaction	QCISD(T)					2.5785 3			2.3869 1					2.7302 2	2.6978 2		2.7292 2	2.7063 2
Coupled Cluster	CCD		2.7868 2	2.6865 2	2.8153 2	2.5651 7	2.6704 2	2.6667 2	2.5651 3	2.6556 2	2.6860 2			2.6207 3	2.6978 2		2.7269 2	2.7032 2
	CCSD					2.8641 7			2.3859 1
	CCSD(T)					2.3956 1	2.3956 1		2.3868 1			2.4011 1		2.6211 3	2.6002 3	2.8597 1	2.6285 3	2.6084 3
	CCSD(T)=FULL					2.6662 2										2.7829 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	2.7139 7	2.6476 7	2.6429 7	2.5856 7	2.6341 7	2.6138 7
density functional	B1B95	2.5028 1	2.5876 5
density functional	B3LYP	2.7079 7	2.6481 7	2.6498 7	2.5959 7	2.6366 7	2.5832 7
Moller Plesset perturbation	MP2FC	2.7249 7	2.6347 7	2.6590 7	2.5705 7	2.6355 7	2.6235 7

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.