III.G.1.a.

Comparison of levels of theory for H-Mg

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	2.2228 2
	PM3	1.6932 5
	PM6	1.7138 5
composite	G2	1.7508 5
	G3	1.7508 5
	G3B3	1.7534 5
	CBS-Q	1.7508 5

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-pCVDZ	cc-pCVTZ
hartree fock	HF	1.6220 4	1.7587 5	1.7536 5	1.7604 5	1.7281 3	1.7463 5	1.7379 5	1.7468 5	1.7421 5	1.7372 5	1.7152 3	1.7336 5	1.7449 5	1.7691 2	1.7337 5	1.7632 2	1.7326 5	1.7306 5	1.7099 2	1.7066 2
hartree fock	ROHF		1.7502 1	1.7439 1		1.7409 1	1.7362 1	1.7362 1	1.7363 1
density functional	LSDA	1.6482 5	1.7708 5	1.7654 5	1.7750 5	1.7606 5	1.7569 5	1.7511 5	1.7570 5	1.7530 5	1.7471 5			1.7596 5	1.7466 5	1.7786 2	1.7511 5	1.7724 2	1.7688 2
	SVWN		1.7776 5			1.7606 5		1.7511 5
	BLYP	1.6751 4	1.7782 5	1.7675 5	1.7788 5	1.7658 5	1.7614 5	1.7549 5	1.7636 5	1.7592 5	1.7526 5			1.8107 2	1.7948 2		1.7308 3
	B1B95	1.6448 5	1.7624 5	1.7581 5	1.7662 5	1.7531 5	1.7504 5	1.7438 5	1.7512 5	1.7473 5	1.7415 5			1.7513 5	1.7408 5	1.7709 2	1.7433 5	1.7651 2	1.7611 2
	B3LYP	1.6518 5	1.7659 5	1.7560 5	1.7660 5	1.7534 5	1.7491 5	1.7427 5	1.7509 5	1.7881 2	1.7409 5	1.7156 3	1.7395 5	1.7503 5	1.7794 2	1.7376 5	1.7774 2	1.7355 5	1.7320 5	1.7057 2	1.7010 2
	B3LYPultrafine					1.7533 5
	B3PW91	1.7352 2	1.7720 5	1.7625 5	1.7692 5	1.7560 5	1.7520 5	1.7461 5	1.7526 5	1.7878 2	1.7435 5			1.7940 2	1.7788 2		1.7238 3
	mPW1PW91	1.7020 3	1.7697 5	1.7945 2	1.7669 5	1.7537 5	1.7497 5	1.7440 5	1.7501 5	1.7460 5	1.7411 5			1.7905 2	1.7755 2		1.7222 3
	M06-2X					1.7435 5
	PBEPBE	1.7538 2	1.7849 5	1.8118 2	1.8299 2	1.7690 5	1.7651 5	1.7591 5	1.7660 5	1.7619 5	1.7560 5	1.7301 3		1.7666 5	1.7561 5	1.7881 2			1.7772 2
	PBEPBEultrafine					1.7413 3
	HSEh1PBE					1.7564 5
Moller Plesset perturbation	MP2FC	1.7156 2	1.7727 5	1.7584 5	1.7742 5	1.7553 5	1.7401 5	1.7328 5	1.7512 5	1.7371 5	1.7485 3		1.7292 5	1.7411 5	1.7694 2	1.7518 3	1.7613 3	1.7334 5	1.7481 3	1.7056 2	1.7038 2
	MP2FU	1.7162 2	1.7732 5	1.7906 2	1.8171 2	1.7550 5	1.7398 5	1.7326 5	1.7516 5	1.7726 2	1.7547 2			1.7785 2	1.7571 2	1.7361 3	1.7156 3		1.7342 2	1.7029 2	1.6930 2
	MP3					1.7602 5
	MP4		1.7884 5			1.7651 5			1.7355 3	1.7762 2					1.7418 5
	B2PLYP					1.7513 5		1.7369 5
Configuration interaction	CID		1.8304 2	1.8046 2	1.8369 2	1.7666 5			1.7640 5
Configuration interaction	CISD		1.7950 5	1.8099 2	1.8435 2	1.7707 5			1.8092 2
Quadratic configuration interaction	QCISD		1.7963 5	1.7845 5	1.8452 2	1.7714 5	1.7483 5	1.7417 5	1.7683 5	1.7439 5	1.7627 2			1.7474 5	1.7447 5
Quadratic configuration interaction	QCISD(T)					1.7352 4	1.7251 3	1.7251 3	1.7417 3					1.7864 2	1.7785 2		1.7843 2	1.7718 2
Coupled Cluster	CCD		1.7912 5	1.8050 2	1.8379 2	1.7671 5	1.7446 5	1.7379 5	1.7646 5	1.7773 2	1.7592 2			1.7439 5	1.7767 2		1.7811 2	1.7690 2		1.7067 2	1.7084 2
	CCSD					1.7714 5	1.7244 3	1.7244 3	1.7409 3
	CCSD(T)		1.7993 1			1.7466 3	1.7251 3	1.7250 3	1.7416 3	1.7414 1		1.7444 1		1.7477 5	1.7452 5		1.7517 5	1.7433 5		1.7088 2	1.7100 2
	CCSD(T)=FULL					1.7949 3								1.7100 2	1.6963 2					1.7068 2	1.7002 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	1.7815 5	1.7562 5	1.7562 5	1.7510 5	1.7450 5	1.7489 5
density functional	B1B95	1.7619 3	1.7355 3
density functional	B3LYP	1.7831 5	1.7615 5	1.7677 5	1.7598 5	1.7499 5	1.7541 5
Moller Plesset perturbation	MP2FC	1.7976 5	1.7709 5	1.7714 5	1.7580 5	1.7610 5	1.7633 5

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.