III.G.1.a.

Comparison of levels of theory for H-Be

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	1.3555 2
	PM3	1.3076 5
	PM6	1.3402 5
composite	G2	1.3654 5
	G3	1.3654 5
	G3B3	1.3665 5
	CBS-Q	1.3668 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	1.3153 5	1.3720 5	1.3720 5	1.3725 5	1.3655 5	1.3646 5	1.3486 5	1.3574 5	1.3543 5	1.3589 5	1.3340 3	1.3493 5	1.3657 5	1.3745 2	1.3478 5	1.3688 2	1.3450 5	1.3434 5	1.3372 2	1.3315 2
hartree fock	ROHF	1.3003 1	1.3541 1	1.3541 1	1.3516 1	1.3459 1	1.3451 1	1.3444 1	1.3447 1	1.3411 1	1.3411 1	1.3391 1		1.3503 1	1.3419 1		1.3455 1	1.3400 1
density functional	LSDA	1.3435 5	1.3926 5	1.3926 5	1.3923 5	1.3837 5	1.3825 5	1.3682 5	1.3716 5	1.3699 5	1.3754 5			1.3863 5	1.3655 5		1.3712 5
	SVWN		1.3926 5			1.3838 5		1.3683 5
	BLYP	1.3491 4	1.3815 5	1.3815 5	1.3809 5	1.3734 5	1.3715 5	1.3576 5	1.3616 5	1.3593 5	1.3652 5			1.3731 5	1.3846 2		1.3421 3
	B1B95	1.3364 5	1.3782 5	1.3782 5	1.3781 5	1.3711 5	1.3699 5	1.3551 5	1.3603 5	1.3576 5	1.3635 5			1.3713 5	1.3537 5	1.3774 2	1.3563 5	1.3680 2	1.3654 2
	B3LYP	1.3345 5	1.3741 5	1.3741 5	1.3738 5	1.3666 5	1.3648 5	1.3510 5	1.3557 5	1.3842 2	1.3588 5	1.3313 3	1.3525 5	1.3666 5	1.3764 2	1.3466 5	1.3763 2	1.3434 5	1.3420 5	1.3328 2	1.3253 2
	B3LYPultrafine					1.3666 5
	B3PW91	1.3755 2	1.3811 5	1.3811 5	1.3808 5	1.3727 5	1.3714 5	1.3567 5	1.3624 5	1.3910 2	1.3653 5			1.4115 2	1.3831 2		1.3434 3
	mPW1PW91	1.3552 3	1.3796 5	1.4245 2	1.3794 5	1.3715 5	1.3703 5	1.3556 5	1.3618 5	1.3590 5	1.3640 5			1.4099 2	1.3821 2		1.3425 3
	M06-2X					1.3672 5
	PBEPBE	1.3905 2	1.3907 5	1.4390 2	1.4462 2	1.3821 5	1.3807 5	1.3659 5	1.3713 5	1.3690 5	1.3741 5	1.3445 3		1.3827 5	1.3646 5	1.3897 2			1.3771 2
	PBEPBEultrafine					1.3490 3
	HSEh1PBE					1.3737 5
Moller Plesset perturbation	MP2FC	1.3671 2	1.3811 5	1.3811 5	1.3825 5	1.3649 5	1.3570 5	1.3428 5	1.3606 5	1.3527 5	1.3719 3		1.3455 5	1.3652 5	1.3751 2	1.3597 3	1.3668 3	1.3449 5	1.3529 3	1.3352 2	1.3289 2
	MP2FU	1.3672 2	1.3809 5	1.4246 2	1.4324 2	1.3642 5	1.3562 5	1.3419 5	1.3600 5	1.3793 2	1.3849 2			1.3988 2	1.3536 3	1.3542 3	1.3520 5		1.3537 2	1.3342 2	1.3260 2
	MP3					1.3673 5
	MP4		1.3904 5			1.3700 5			1.3453 3	1.3853 2					1.3551 5
	B2PLYP					1.3643 5		1.3471 5
Configuration interaction	CID		1.4364 2	1.4364 2	1.4450 2	1.3708 5			1.3692 5
Configuration interaction	CISD		1.3931 5	1.4393 2	1.4479 2	1.3721 5			1.4062 2
Quadratic configuration interaction	QCISD		1.3937 5	1.3923 5	1.4487 2	1.3723 5	1.3597 5	1.3450 5	1.3712 5	1.3563 5	1.3911 2			1.3693 5	1.3564 5
Quadratic configuration interaction	QCISD(T)					1.3729 5	1.3329 3	1.3336 3	1.3482 3					1.4060 2	1.3835 2		1.3834 2	1.3701 2
Coupled Cluster	CCD		1.3916 5	1.4370 2	1.4455 2	1.3708 5	1.3581 5	1.3436 5	1.3696 5	1.3856 2	1.3896 2			1.3678 5	1.3822 2		1.3817 2	1.3683 2		1.3358 2	1.3320 2
	CCSD					1.3412 4	1.3324 3	1.3332 3	1.3476 3
	CCSD(T)		1.3806 1			1.3729 5	1.3328 3	1.3336 3	1.3482 3	1.3471 1		1.3501 1		1.3698 5	1.3570 5	1.3780 2	1.3611 5	1.3511 5	1.3671 2	1.3369 2	1.3326 2
	CCSD(T)=FULL					1.4138 2										1.3722 2			1.3605 2	1.3358 2	1.3295 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	1.3822 5	1.3615 5	1.3593 5	1.3589 5	1.3702 5	1.3562 5
density functional	B1B95	1.3561 3	1.3418 3
density functional	B3LYP	1.3829 5	1.3659 5	1.3662 5	1.3639 5	1.3710 5	1.3589 5
Moller Plesset perturbation	MP2FC	1.3954 5	1.3692 5	1.3713 5	1.3624 5	1.3809 5	1.3647 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.