III.G.1.a.

Comparison of levels of theory for Al-H

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	1.4378 9
	PM3	1.6499 16
	PM6	1.6355 25
composite	G2	1.6224 19
	G3	1.6224 19
	G3B3	1.6304 19
	CBS-Q	1.6224 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(D+d)Z	cc-pV(T+d)Z	cc-pCVDZ	cc-pCVTZ
hartree fock	HF	1.5543 19	1.6872 25	1.6561 25	1.6888 25	1.6546 25	1.6471 25	1.6446 25	1.6430 25	1.6402 25	1.6393 25	1.5935 6	1.6288 25	1.6506 25	1.6450 25	1.6378 21	1.6483 25	1.6418 25	1.6359 21	1.6512 1	1.6146 10	1.5849 3	1.5790 3
hartree fock	ROHF	1.5274 10	1.7126 15	1.6725 15	1.7269 13	1.6657 17	1.6553 15	1.6664 15	1.6542 15	1.6539 13	1.6171 10			1.6564 15	1.6511 15	1.6575 13	1.6640 13	1.6560 13	1.6691 10
density functional	LSDA	1.5593 25	1.6610 25	1.6475 25	1.6702 25	1.6497 25	1.6456 25	1.6450 25	1.6430 25	1.6430 25	1.6394 25			1.6536 25	1.6422 25	1.6338 9	1.6499 25	1.6466 12	1.6301 9	1.6872 1	1.6752 1
	SVWN		1.6604 22			1.6402 19		1.6402 22
	BLYP	1.5832 19	1.6695 25	1.6488 25	1.6745 25	1.6509 25	1.6467 25	1.6458 25	1.6462 25	1.6451 25	1.6404 25			1.6552 25	1.6445 25		1.6208 6			1.6851 1	1.6737 1
	B1B95	1.5600 21	1.6447 21	1.6404 21	1.6665 21	1.6398 21	1.6387 21	1.6360 21	1.6427 21	1.6410 21	1.6326 21			1.6460 21	1.6375 21	1.6287 12	1.6320 14	1.6486 9	1.6251 12	1.6686 1	1.6608 1
	B3LYP	1.5595 25	1.6621 25	1.6405 25	1.6666 25	1.6417 25	1.6381 25	1.6371 25	1.6370 25	1.6462 19	1.6327 25	1.6199 3	1.6323 25	1.6447 25	1.6369 25	1.6299 21	1.6426 25	1.6341 25	1.6278 21	1.6704 1	1.6148 10
	B3LYPultrafine					1.6413 25		1.6055 2
	B3PW91	1.5697 19	1.6670 25	1.6460 25	1.6693 25	1.6446 25	1.6420 25	1.6404 25	1.6408 25	1.6502 19	1.6369 25			1.6495 25	1.6412 25		1.6132 6			1.6717 1	1.6638 1
	mPW1PW91	1.5566 25	1.6664 25	1.6549 19	1.6686 25	1.6433 25	1.6411 25	1.6396 25	1.6400 25	1.6389 25	1.6358 25			1.6485 25	1.6405 25		1.6518 9	1.7242 3		1.6685 1	1.6613 1
	M06-2X					1.6265 22														1.6589 1	1.6491 1
	PBEPBE	1.5821 19	1.6776 25	1.6656 19	1.6920 19	1.6567 25	1.6533 25	1.6526 25	1.6524 25	1.6514 25	1.6483 25	1.6361 3		1.6622 25	1.6522 25	1.6400 9	1.7325 3	1.6527 9	1.6354 9	1.6889 1	1.6794 1
	PBEPBEultrafine					1.6250 6
	HSEh1PBE					1.6364 22														1.6721 1	1.6643 1
Moller Plesset perturbation	MP2FC	1.5668 19	1.6914 25	1.6535 25	1.6985 25	1.6519 25	1.6347 25	1.6331 25	1.6423 25	1.6311 25	1.6291 25		1.6227 25	1.6431 25	1.6365 25	1.6937 6	1.6454 25	1.6341 21	1.6927 6	1.6500 1	1.6102 10	1.5834 3	1.5767 3
	MP2FU	1.5668 19	1.6914 25	1.6680 19	1.7203 19	1.6510 25	1.6332 25	1.6322 25	1.6423 25	1.6428 19	1.6365 19			1.6423 25	1.6457 19	1.6347 6	1.6568 9	1.6428 13	1.6408 5	1.6491 1	1.6051 10	1.5822 3	1.5712 3
	ROMP2	1.5735 13	1.6972 13	1.6791 13	1.7367 13	1.6754 13	1.6528 13	1.6516 13	1.6628 13	1.6473 13	1.6467 13			1.6608 13	1.6539 13	1.6184 10	1.6639 13	1.6204 10	1.6225 7
	MP3					1.6543 25														1.6500 1	1.6489 1
	MP4		1.7022 25			1.6568 25			1.6053 6	1.6441 19					1.6485 15					1.6512 1	1.6513 1
	B2PLYP					1.6293 22		1.6219 22												1.6595 1	1.6523 1
Configuration interaction	CID		1.7227 19	1.6727 19	1.7316 19	1.6571 25			1.6490 25						1.5987 6
Configuration interaction	CISD		1.7049 25	1.6723 19	1.7342 19	1.6575 25			1.6636 19						1.5996 6
Quadratic configuration interaction	QCISD		1.7068 25	1.6668 25	1.7363 19	1.6585 25	1.6373 25	1.6355 25	1.6555 22	1.6337 25	1.6430 19			1.6462 21	1.6409 21		1.7657 3	1.7423 3		1.6513 1	1.6509 1
Quadratic configuration interaction	QCISD(T)					1.6586 25	1.5978 6	1.5969 6	1.6089 6					1.6470 21	1.6413 21		1.6428 12	1.6334 6
Coupled Cluster	CCD		1.7043 25	1.6732 19	1.7333 19	1.6580 25	1.6359 25	1.6346 25	1.6501 25	1.6448 19	1.6416 19			1.6443 21	1.6394 21		1.6648 15	1.6698 9		1.6500 1	1.6500 1
	CCSD					1.6583 25	1.5969 6	1.5960 6	1.6078 6					1.6532 9	1.6479 9
	CCSD(T)		1.7148 1			1.6616 15	1.5977 6	1.5969 6	1.6088 6	1.6481 1				1.6469 21	1.6413 21	1.6998 5	1.6542 18	1.6479 12	1.6986 5	1.6526 1	1.6232 12	1.5871 3	1.5824 3
	CCSD(T)=FULL					1.6448 14								1.6661 6	1.6564 6	1.6354 5	1.6704 6	1.6537 6	1.6336 5	1.6521 1	1.6500 1	1.5864 3	1.5777 3

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	1.6859 25	1.6574 25	1.6810 25	1.6540 25	1.6760 25	1.6637 25
density functional	B1B95	1.6365 6	1.6199 6
density functional	B3LYP	1.6710 25	1.6523 25	1.6678 25	1.6540 25	1.6635 25	1.6499 25
Moller Plesset perturbation	MP2FC	1.6961 25	1.6622 25	1.6901 25	1.6575 25	1.6874 25	1.6712 25

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.