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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 1.4914
3
PM3 1.3467
6
PM6 1.3671
6
composite G2 1.3718
5
G3 1.3591
6
G3B3 1.3800
6
G4 1.3732
4
CBS-Q 1.3625
6

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 1.3373
5
1.3890
6
1.3883
5
1.3888
5
1.3711
10
1.3585
6
1.3605
6
1.3533
6
1.3533
6
1.3543
6
1.3236
3
1.3679
6
1.3737
6
1.3556
4
1.3508
6
1.3809
4
1.3545
6
1.3519
6
ROHF 1.3507
2
1.4162
4
1.4162
4
1.4311
3
1.3900
4
1.3892
4
1.3906
4
1.3836
4
1.3814
3
1.3686
2
  1.4195
1
1.4046
3
1.3812
3
1.3778
3
1.4040
3
1.3814
3
1.3787
3
density functional LSDA 1.3770
6
1.4073
6
1.4074
6
1.4082
6
1.3787
6
1.3791
6
1.3802
6
1.3723
6
1.3719
6
1.3735
6
  1.3927
2
1.3933
6
1.3729
6
1.3852
2
1.3917
6
1.3811
4
1.3861
2
SVWN   1.4073
6
    1.3787
6
1.3796
2
1.3803
6
1.3742
2
1.3742
2
1.3761
2
    1.3964
2
1.3735
2
  1.3916
2
1.3725
2
 
BLYP 1.4008
5
1.4221
5
1.4275
5
1.4380
4
1.3961
6
1.3958
6
1.4082
5
1.3982
5
1.3887
6
1.3901
6
  1.4079
2
1.4079
6
1.3968
4
  1.3829
3
   
B1B95 1.3695
6
1.4051
6
1.4051
6
1.4072
6
1.3781
6
1.3789
6
1.3710
5
1.3726
6
1.3727
6
1.3737
6
  1.3862
2
1.3930
6
1.3717
6
1.3856
2
1.3927
6
1.3612
1
1.4151
1
B3LYP 1.3704
6
1.4051
6
1.4069
5
1.4178
5
1.3800
6
1.3798
6
1.3818
6
1.3831
5
1.3807
4
1.3744
6
1.3448
3
1.3870
5
1.3927
6
1.3808
4
1.3697
6
1.4013
4
1.3743
6
1.3708
6
B3LYPultrafine         1.3800
6
  1.3987
1
          1.3931
2
1.3803
3
  1.3914
2
1.3744
4
 
B3PW91 1.3946
4
1.4095
5
1.4170
5
1.4204
5
1.3806
6
1.3804
6
1.3926
5
1.3850
5
1.3824
4
1.3762
6
  1.3896
2
1.4251
3
1.4006
3
  1.3675
3
   
mPW1PW91 1.3765
5
1.4046
6
1.4189
4
1.4066
6
1.3778
6
1.3775
6
1.3795
6
1.3713
6
1.3715
6
1.3730
6
  1.3863
2
1.4007
4
1.3783
4
  1.3844
4
1.3683
2
 
M06-2X 1.3755
2
1.4031
2
1.4031
2
1.4037
2
1.3729
6
1.3699
2
1.3728
2
1.3654
2
1.3654
2
1.3674
2
  1.3807
2
1.3848
2
1.3655
2
  1.3840
2
1.3649
2
 
PBEPBE 1.4138
4
1.4206
6
1.4354
4
1.4397
4
1.3959
6
1.3955
6
1.3979
6
1.3888
6
1.3890
6
1.3903
6
1.3605
3
1.4072
2
1.4096
6
1.3889
6
1.4005
2
1.4089
2
1.3872
2
1.4016
2
PBEPBEultrafine         1.3946
5
              1.4114
2
1.3877
2
  1.4089
2
1.3871
2
 
PBE1PBE 1.3893
2
1.4127
2
1.4127
2
1.4135
2
1.3781
6
1.3754
2
1.3779
2
1.3700
2
1.3700
2
1.3722
2
  1.3869
2
1.3927
2
1.3695
2
  1.3903
2
1.3689
2
 
HSEh1PBE 1.3897
2
1.4127
2
1.4127
2
1.4134
2
1.3781
6
1.3753
2
1.3778
2
1.3701
2
1.3701
2
1.3721
2
  1.3871
2
1.3925
2
1.3697
2
  1.3902
2
1.3691
2
 
TPSSh   1.3668
1
1.3668
1
1.3616
1
1.3737
4
1.3354
1
1.3762
4
1.3291
1
        1.3459
1
1.3687
4
  1.3466
1
1.3302
1
 
Moller Plesset perturbation MP2 1.3914
4
1.4222
6
1.4222
6
1.4355
5
1.3961
6
1.3962
6
1.4034
8
1.3874
6
1.3895
6
1.3908
6
  1.4035
6
1.4132
6
1.3953
4
1.3822
5
1.4166
5
1.3942
6
1.3849
5
MP2=FULL 1.3914
4
1.4221
6
1.4321
4
1.4443
4
1.3917
6
1.3924
6
1.3948
6
1.3847
6
1.3916
4
1.3842
4
  1.4064
2
1.4166
4
1.3906
4
1.3757
5
1.4045
4
1.3881
4
1.3757
3
ROMP2 1.4119
3
1.4103
1
1.4103
1
1.4159
1
1.4170
3
1.4170
3
1.4229
3
1.4109
3
1.4109
3
1.4113
3
  1.4449
1
1.4370
3
1.4117
3
1.3994
2
1.4429
3
1.4083
2
1.4027
2
MP3         1.3769
6
  1.3671
4
                     
MP3=FULL         1.3646
4
  1.3679
4
                     
MP4   1.4886
4
    1.4260
5
    1.4099
2
1.4150
4
    1.4456
2
1.4967
2
1.4090
6
  1.4564
2
1.4146
2
 
MP4=FULL   1.5451
2
    1.4398
2
      1.4227
2
      1.4945
2
1.4089
2
  1.4411
2
1.3989
2
 
B2PLYP         1.3885
4
                1.3769
2
       
B2PLYP=FULLultrafine         1.4066
1
                         
Configuration interaction CID   1.4177
4
1.4177
4
1.4275
4
1.3890
5
    1.3798
5
                   
CISD   1.4207
5
1.4263
4
1.4358
4
1.3928
5
    1.3809
4
                   
Quadratic configuration interaction QCISD   1.4331
6
1.4460
4
1.4573
4
1.4013
6
1.4059
4
1.4033
6
1.3985
5
1.3938
6
1.3953
4
  1.4135
2
1.4198
6
1.3881
6
  1.4223
2
1.3879
2
 
QCISD(T)         1.3919
6
    1.3585
3
      1.4021
2
1.4201
4
1.3957
4
  1.4246
4
1.3976
4
 
Coupled Cluster CCD   1.4206
4
1.4206
4
1.4314
4
1.3925
5
1.3880
4
1.3933
4
1.3835
5
1.3805
4
1.3816
4
  1.3891
2
1.3981
6
1.3806
4
  1.4107
4
1.3831
4
 
CCSD         1.3872
6
    1.3516
3
      1.3948
2
1.4042
2
1.3768
2
1.3705
2
1.4058
2
1.3774
2
1.3714
2
CCSD=FULL         1.3822
2
            1.3937
2
1.4022
2
1.3722
2
1.3642
2
1.3960
2
1.3664
2
1.3635
2
CCSD(T)         1.3995
5
1.3728
3
  1.3635
3
    1.3395
2
1.4065
2
1.4113
5
1.3842
5
1.3809
2
1.4146
5
1.3862
5
1.3818
2
CCSD(T)=FULL         1.3861
3
            1.4054
2
1.4146
2
1.3826
2
1.3741
2
1.4070
2
1.3764
2
1.3736
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 1.4001
6
1.3694
6
1.3749
6
1.3577
6
1.4092
6
1.3933
6
density functional B1B95 1.3770
3
1.3782
2
       
B3LYP 1.4332
5
1.4056
5
1.4117
5
1.3941
5
1.4368
5
1.4247
5
Moller Plesset perturbation MP2 1.4458
6
1.4098
6
1.4223
6
1.3978
6
1.4520
6
1.4296
6
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.