III.G.1.a.

Comparison of levels of theory for O-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	1.4850 2
	PM3	1.3539 4
	PM6	1.3862 4
composite	G2	1.3625 4
	G3	1.3625 4
	G3B3	1.3812 4
	CBS-Q	1.3659 4

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
hartree fock	HF	1.3308 3	1.3875 4	1.3860 3	1.3862 3	1.3624 4	1.3615 4	1.3634 4	1.3558 4	1.3559 4	1.3567 4	1.3401 2	1.3707 4	1.3757 4	1.3717 2	1.3537 4	1.3933 2	1.3576 4	1.3550 4
hartree fock	ROHF	1.3507 2	1.4027 3	1.4027 3	1.4151 2	1.3836 3	1.3825 3	1.3841 3	1.3764 3	1.3694 2	1.3686 2			1.3902 2	1.3700 2	1.3669 2	1.3919 2	1.3710 2	1.3681 2
density functional	LSDA	1.3651 4	1.4028 4	1.4029 4	1.4040 4	1.3783 4	1.3789 4	1.3793 4	1.3713 4	1.3707 4	1.3722 4			1.3918 4	1.3726 4	1.3852 2	1.3918 4	1.3897 2	1.3861 2
	SVWN		1.4028 4			1.3783 4		1.3794 4
	BLYP	1.3921 3	1.4181 3	1.4145 4	1.4212 3	1.3967 4	1.3962 4	1.3990 4	1.3885 4	1.3887 4	1.3896 4			1.4069 4	1.4048 2		1.3950 2
	B1B95	1.3589 4	1.4016 4	1.4015 4	1.4043 4	1.3800 4	1.3805 4	1.3814 4	1.3736 4	1.3738 4	1.3744 4			1.3932 4	1.3734 4	1.3856 2	1.3945 4	1.3612 1	1.4151 1
	B3LYP	1.3594 4	1.4013 4	1.4031 3	1.4039 4	1.3812 4	1.3809 4	1.3825 4	1.3734 4	1.3899 2	1.3747 4	1.3572 2	1.3854 3	1.3924 4	1.3899 2	1.3707 4	1.4113 2	1.3757 4	1.3722 4
	B3LYPultrafine					1.3812 4		1.3987 1
	B3PW91	1.3954 2	1.4058 3	1.4039 4	1.4062 4	1.3821 4	1.3817 4	1.3835 4	1.3754 4	1.3919 2	1.3769 4			1.4122 2	1.3907 2		1.3816 2
	mPW1PW91	1.3680 3	1.4009 4	1.4257 2	1.4035 4	1.3793 4	1.3789 4	1.3806 4	1.3722 4	1.3725 4	1.3737 4			1.4095 2	1.3877 2		1.3791 2
	M06-2X					1.3745 4
	PBEPBE	1.4141 2	1.4160 4	1.4409 2	1.4475 2	1.3966 4	1.3960 4	1.3983 4	1.3889 4	1.3891 4	1.3900 4	1.3716 2		1.4087 4	1.3895 4	1.4005 2			1.4016 2
	PBEPBEultrafine					1.3831 2
	HSEh1PBE					1.3795 4
Moller Plesset perturbation	MP2FC	1.3727 2	1.4136 4	1.4136 4	1.4299 3	1.3953 4	1.3955 4	1.4005 4	1.3861 4	1.3893 4	1.3897 4		1.4014 4	1.4113 4	1.3995 2	1.3801 3	1.4147 3	1.3951 4	1.3835 3
	MP2FU	1.3727 2	1.4134 4	1.4248 2	1.4449 2	1.3905 4	1.3914 4	1.3934 4	1.3832 4	1.3953 2	1.3874 2			1.4183 2	1.3950 2	1.3737 3	1.3995 2	1.3948 2	1.3693 1
	ROMP2	1.3938 2	1.4103 1	1.4103 1	1.4159 1	1.4080 2	1.4080 2	1.4153 2	1.4019 2	1.4019 2	1.4015 2			1.4262 2	1.4034 2	1.3994 2	1.4347 2	1.4083 2	1.4027 2
	MP3					1.3783 4
	MP4		1.4322 2			1.4225 4			1.4099 2	1.4039 2					1.4056 4
	B2PLYP					1.3885 4		1.3907 4
Configuration interaction	CID		1.4223 2	1.4223 2	1.4361 2	1.3791 4			1.3694 4
Configuration interaction	CISD		1.4199 3	1.4307 2	1.4435 2	1.3830 4			1.3892 2
Quadratic configuration interaction	QCISD		1.4259 4	1.4445 2	1.4580 2	1.3998 4	1.4074 2	1.4017 4	1.3903 4	1.3927 4	1.3980 2			1.4173 4	1.3879 4
Quadratic configuration interaction	QCISD(T)					1.3934 4			1.3692 2					1.4305 2	1.4033 2		1.4361 2	1.4066 2
Coupled Cluster	CCD		1.4237 2	1.4237 2	1.4389 2	1.3829 4	1.3957 2	1.4025 2	1.3733 4	1.3883 2	1.3885 2			1.3980 4	1.3887 2		1.4205 2	1.3926 2
	CCSD					1.3880 4			1.3632 2
	CCSD(T)					1.4020 3	1.3830 2		1.3728 2			1.3395 1		1.4076 3	1.3820 3		1.4126 3	1.3849 3
	CCSD(T)=FULL					1.3734 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	1.3978 4	1.3726 4	1.3730 4	1.3609 4	1.4072 4	1.3926 4
density functional	B1B95	1.3843 2	1.3782 2
density functional	B3LYP	1.4173 4	1.3957 4	1.3962 4	1.3842 4	1.4213 4	1.4062 4
Moller Plesset perturbation	MP2FC	1.4384 4	1.4091 4	1.4150 4	1.3974 4	1.4445 4	1.4246 4

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.