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Comparison of levels of theory for As-As


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 PM3 2.3922
6
PM6 2.4296
7
composite G2 2.3989
6
G3 2.4215
6
G3B3 2.4628
6
G4 2.4093
7
CBS-Q 2.4014
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 daug-cc-pVDZ daug-cc-pVTZ
hartree fock HF 2.3084
7
2.5182
7
2.3609
7
2.4760
7
2.3499
7
2.3499
7
2.3544
7
2.3724
7
2.3724
7
2.3144
7
2.4160
6
2.3710
7
2.3723
7
2.3667
7
2.4160
6
2.3763
7
2.3670
7
2.4160
6
2.4282
6
2.3670
7
density functional LSDA 2.3085
7
2.3620
7
2.3620
7
2.4706
7
2.3580
7
2.3580
7
2.3632
7
2.3781
7
2.3781
7
2.3148
7
  2.4242
6
2.3832
7
2.3701
7
  2.3841
7
2.3702
7
     
BLYP 2.3463
7
2.5590
7
2.4212
7
2.5356
7
2.4181
7
2.4229
7
2.4283
7
2.4469
7
2.4469
7
2.3697
7
2.4878
6
2.4974
6
2.4506
7
2.4388
7
  2.5032
6
2.4898
6
  2.5032
6
2.4899
6
B1B95 2.3160
7
2.4067
6
2.3613
7
2.4725
7
2.3514
7
2.3514
7
2.3561
7
2.3759
7
2.3759
7
2.3128
7
2.4146
6
2.4231
6
2.3757
7
2.3694
7
  2.3780
7
2.3699
7
  2.4262
6
2.4178
6
B3LYP 2.3335
7
2.5346
7
2.3933
7
2.5065
7
2.3903
7
2.3903
7
2.3954
7
2.4128
7
2.4128
7
2.3437
7
2.4536
6
2.4119
7
2.4159
7
2.4053
7
2.4536
6
2.4176
7
2.4056
7
2.4534
6
2.4683
6
2.4557
6
B3LYPultrafine   2.5962
6
    2.3904
7
2.4393
6
2.4441
6
2.4630
6
  2.3891
6
2.4536
6
2.4621
6
2.4666
6
2.4553
6
  2.4683
6
2.4068
7
  2.4683
6
2.4557
6
B3PW91 2.3271
7
2.5235
7
2.3785
7
2.4893
7
2.3705
7
2.3705
7
2.3750
7
2.3928
7
2.3928
7
2.3281
7
2.4323
6
2.4408
6
2.3950
7
2.3858
7
  2.4462
6
2.4348
6
  2.4462
6
2.4350
6
mPW1PW91 2.3235
7
2.5189
7
2.3731
7
2.4831
7
2.3637
7
2.3637
7
2.3683
7
2.3859
7
2.3859
7
2.3228
7
2.4257
6
2.4338
6
2.3877
7
2.3793
7
  2.3899
7
2.3796
7
  2.4391
6
2.4285
6
M06-2X 2.3652
6
2.5867
6
2.3776
7
2.5396
6
2.4020
6
2.4020
6
2.4062
6
2.4294
6
2.4294
6
2.3655
6
2.3737
7
2.4350
6
2.4279
6
2.4290
6
  2.4316
6
2.4295
6
  2.4317
6
2.4296
6
PBEPBE 2.3318
7
2.5418
7
2.3980
7
2.5111
7
2.3913
7
2.3913
7
2.3961
7
2.4155
7
2.4155
7
2.3448
7
2.4543
6
2.4638
6
2.4174
7
2.4085
7
  2.4191
7
2.4090
7
  2.4679
6
2.4575
6
PBEPBEultrafine   2.6015
6
    2.4382
6
2.4382
6
2.4428
6
2.4638
6
  2.3885
6
2.4543
6
2.4635
6
2.4661
6
2.4567
6
  2.4679
6
2.4573
6
  2.4679
6
2.4575
6
PBE1PBE 2.3756
6
2.4183
6
2.4183
6
2.5445
6
2.3621
7
2.4091
6
2.4135
6
2.4330
6
2.4330
6
2.3655
6
2.4243
6
2.4324
6
2.4348
6
2.4264
6
  2.4372
6
2.4269
6
  2.4373
6
2.4271
6
HSEh1PBE 2.3761
6
2.5819
6
2.4199
6
2.5495
6
2.4125
6
2.4125
6
2.4171
6
2.4367
6
2.4367
6
2.3682
6
2.4278
6
2.4361
6
2.4388
6
2.4302
6
  2.4410
6
2.4305
6
  2.4412
6
2.4309
6
TPSSh 2.3820
6
2.5896
6
2.4244
6
2.5513
6
2.3682
7
2.4145
6
2.3726
7
2.4400
6
2.4400
6
2.3234
7
2.4301
6
2.4392
6
2.4415
6
2.3840
7
2.4305
6
2.4434
6
2.4327
6
2.4305
6
2.4435
6
2.4329
6
wB97X-D 2.3718
6
2.5680
6
2.3699
7
2.5328
6
2.3585
7
2.4085
6
2.3633
7
2.4291
6
2.3790
7
2.3661
6
2.4204
6
2.3805
7
2.3802
7
2.3739
7
2.4231
6
2.4348
6
2.3741
7
2.4229
6
2.4348
6
2.4247
6
B97D3 2.4040
6
2.5483
7
2.4436
6
2.5785
6
2.3960
7
2.4435
6
2.4015
7
2.4722
6
2.4233
7
2.3914
6
2.4122
7
2.4208
7
2.4737
6
2.4128
7
2.4589
6
2.4756
6
2.4126
7
2.4585
6
2.4755
6
2.4127
7
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 daug-cc-pVDZ daug-cc-pVTZ
Moller Plesset perturbation MP2 2.3788
7
2.6100
7
2.4010
7
2.5709
7
2.4044
7
2.4050
7
2.4101
7
2.4247
7
2.4287
7
2.3472
7
2.4518
6
2.4058
7
2.4146
7
2.3872
7
2.4125
6
2.4271
7
2.3877
7
2.4082
6
2.4717
6
2.4310
6
MP2=FULL 2.3782
7
2.6100
7
2.3978
7
2.5703
7
2.3915
7
2.3915
7
2.3967
7
2.4159
7
2.4159
7
2.3198
7
2.4289
6
2.4478
6
2.4113
7
2.3742
7
2.4078
6
2.4247
7
2.3656
7
2.3985
6
2.4695
6
2.4094
6
MP3         2.3984
7
  2.3980
7
        2.4536
6
2.4617
6
2.4321
6
        2.4698
6
2.4319
6
MP3=FULL   2.6511
6
2.4411
6
2.6133
6
2.3874
7
2.4353
6
2.3919
7
2.4638
6
2.4638
6
2.3650
6
2.4334
6
2.4541
6
2.4591
6
2.4220
6
  2.4684
6
2.4135
6
     
MP4   2.6030
7
    2.4141
7
      2.4385
7
  2.4616
6
2.4660
6
2.4728
6
2.3990
7
  2.4847
6
2.4438
6
  2.4847
6
2.4438
6
MP4=FULL   2.6621
6
    2.4444
6
      2.4742
6
  2.4418
6
  2.4689
6
2.4293
6
  2.4822
6
2.4204
6
  2.4823
6
2.4225
6
B2PLYP 2.4030
6
2.6217
6
2.4402
6
2.5905
6
2.4408
6
2.4408
6
2.4458
6
2.4658
6
2.4658
6
2.3877
6
2.4533
6
2.4580
6
2.4629
6
2.4012
7
  2.4694
6
2.4484
6
  2.4694
6
2.4484
6
B2PLYP=FULL 2.4027
6
2.6217
6
2.4392
6
2.5903
6
2.4362
6
2.4362
6
2.4412
6
2.4620
6
2.4620
6
2.3796
6
2.4461
6
2.4575
6
2.4618
6
2.4435
6
  2.4686
6
2.4412
6
  2.4687
6
2.4418
6
B2PLYP=FULLultrafine 2.4030
6
2.6214
6
2.4390
6
2.5903
6
2.3905
7
2.4363
6
2.4413
6
2.4620
6
2.4620
6
2.3797
6
2.4461
6
2.4574
6
2.4145
7
2.3969
7
  2.4686
6
2.3947
7
  2.4687
6
2.4418
6
Configuration interaction CID   2.5589
7
2.3759
7
2.5195
7
2.3752
7
    2.3947
7
    2.4223
6
  2.4362
6
2.4063
6
        2.4409
6
2.4050
6
CISD   2.5603
7
2.3766
7
2.5211
7
2.3761
7
    2.3957
7
    2.4231
6
  2.4369
6
2.4064
6
        2.4413
6
2.4052
6
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 daug-cc-pVDZ daug-cc-pVTZ
Quadratic configuration interaction QCISD   2.5929
7
2.3974
7
2.5542
7
2.3988
7
2.3988
7
2.4031
7
2.4203
7
2.4203
7
2.3407
7
2.4450
6
2.4520
6
2.4120
7
2.3817
7
  2.4189
7
2.3806
7
  2.4674
6
2.4276
6
QCISD(T)         2.4118
7
    2.4825
6
    2.4584
6
2.4657
6
2.4255
7
2.3954
7
  2.4825
6
2.4417
6
  2.4824
6
2.4416
6
QCISD(T)=FULL         2.4443
6
  2.4487
6
      2.4412
6
  2.4694
6
2.4294
6
  2.4802
6
2.4202
6
     
Coupled Cluster CCD   2.5885
7
2.3943
7
2.5495
7
2.3956
7
2.3956
7
2.4000
7
2.4166
7
2.4166
7
2.3380
7
2.4421
6
2.4483
6
2.4083
7
2.3782
7
  2.4157
7
2.3777
7
  2.4646
6
2.4252
6
CCSD         2.3980
7
2.4448
6
2.4490
6
2.4678
6
2.4678
6
2.3834
6
2.4444
6
2.4515
6
2.4113
7
2.3813
7
2.4103
6
2.4672
6
2.4276
6
2.4064
6
2.4670
6
2.4275
6
CCSD=FULL         2.4325
6
        2.3615
6
2.4277
6
2.4501
6
2.4564
6
2.4168
6
  2.4652
6
2.4073
6
     
CCSD(T)         2.4112
7
2.4571
6
2.4615
6
2.4819
6
2.4819
6
2.3928
6
2.4580
6
2.4652
6
2.4249
7
2.3952
7
2.4230
6
2.4338
7
2.3948
7
2.4183
6
2.4820
6
2.4413
6
CCSD(T)=FULL         2.3989
7
            2.4639
6
2.4216
7
2.3838
7
  2.4316
7
2.3750
7
     
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 daug-cc-pVDZ daug-cc-pVTZ

average calculated bond lengths (Å)
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 2.4573
7
  2.4573
7
  2.5158
7
2.4601
7
2.4110
6
  2.3625
7
ROHF             2.4110
6
   
density functional LSDA             2.4174
6
   
BLYP             2.4889
6
  2.4865
6
B1B95             2.4162
6
  2.4152
6
B3LYP 2.5086
7
  2.5086
7
  2.5617
7
2.5054
7
2.4538
6
  2.4032
7
B3LYPultrafine             2.4538
6
  2.4528
6
B3PW91             2.4329
6
  2.4323
6
mPW1PW91             2.4258
6
  2.4258
6
M06-2X             2.4284
6
  2.4286
6
PBEPBE             2.4562
6
  2.4066
7
PBEPBEultrafine             2.4562
6
  2.4540
6
PBE1PBE             2.4245
6
  2.4244
6
HSEh1PBE             2.4284
6
  2.4278
6
TPSSh             2.4309
6
  2.4302
6
wB97X-D 2.5298
6
  2.5298
6
  2.5837
6
2.5253
6
2.4227
6
  2.4235
6
B97D3             2.4634
6
  2.4583
6
Moller Plesset perturbation MP2 2.5763
7
  2.5763
7
  2.6294
7
2.5696
7
2.4228
6
  2.3798
7
MP2=FULL             2.4157
6
  2.4113
6
MP3             2.4247
6
  2.4255
6
MP3=FULL             2.4198
6
  2.4190
6
MP4             2.4354
6
  2.4353
6
MP4=FULL             2.4279
6
  2.4250
6
B2PLYP             2.4438
6
  2.4433
6
B2PLYP=FULL             2.4416
6
  2.4402
6
B2PLYP=FULLultrafine             2.4416
6
  2.4402
6
Configuration interaction CID             2.3988
6
  2.3987
6
CISD             2.3991
6
  2.3989
6
Quadratic configuration interaction QCISD             2.4207
6
  2.4219
6
QCISD(T)             2.4341
6
  2.4346
6
QCISD(T)=FULL             2.4275
6
  2.4257
6
Coupled Cluster CCD             2.4181
6
  2.4187
6
CCSD             2.4206
6
  2.4217
6
CCSD=FULL             2.4147
6
  2.4132
6
CCSD(T)             2.4338
6
  2.4343
6
CCSD(T)=FULL             2.4274
6
  2.4254
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.