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III.G.1.a.

Comparison of levels of theory for Be-N


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 1.4880
4
PM3 1.4682
4
PM6 1.4117
6
composite G2 1.4934
4
G3 1.4934
4
G3B3 1.5254
4
G4 1.5199
3
CBS-Q 1.4929
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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
hartree fock HF 1.5190
4
1.5353
4
1.5353
4
1.5286
4
1.4979
6
1.4932
4
1.4960
4
1.4883
4
1.4883
4
1.4899
4
1.5924
5
1.4962
4
1.4907
4
1.4886
4
1.5023
4
1.4931
4
1.4899
4
ROHF 1.4669
2
1.5311
4
1.5311
4
1.5249
4
1.4906
4
1.4906
4
1.4928
4
1.4849
4
1.4849
4
1.4647
2
1.5341
2
1.4932
4
1.4879
4
1.4886
4
1.4989
4
1.4902
4
1.4899
4
density functional LSDA 1.5424
4
1.5567
4
1.5567
4
1.5511
4
1.5226
4
1.5226
4
1.5249
4
1.5153
4
1.5153
4
1.5191
4
1.5546
2
1.5262
4
1.5166
4
1.4946
2
1.5270
4
1.5181
4
1.4960
2
SVWN   1.5738
5
    1.5284
4
1.5420
2
1.5377
5
1.5339
2
1.5339
2
1.5392
2
  1.5444
2
1.5352
2
  1.5454
2
1.5363
2
 
BLYP 1.5601
4
1.5716
4
1.5716
4
1.5684
4
1.5402
4
1.5402
4
1.5435
4
1.5327
4
1.5327
4
1.5368
4
1.5748
2
1.5424
4
1.5345
4
       
B1B95 1.5421
4
1.5611
4
1.5611
4
1.5573
4
1.5266
4
1.5266
4
1.5038
3
1.5200
4
1.5200
4
1.5231
4
1.5652
2
1.5301
4
1.5216
4
1.4945
2
1.5342
4
1.5330
3
1.4961
2
B3LYP 1.5433
4
1.5597
4
1.5597
4
1.5555
4
1.5258
4
1.5258
4
1.5284
4
1.5186
4
1.5186
4
1.5226
4
1.5531
5
1.5283
4
1.5205
4
1.5174
4
1.5324
4
1.5226
4
1.5189
4
B3LYPultrafine         1.5258
4
            1.5521
2
1.5445
2
  1.5562
2
1.5239
4
 
B3PW91 1.5431
4
1.5637
4
1.5637
4
1.5592
4
1.5281
4
1.5281
4
1.5302
4
1.5220
4
1.5220
4
1.5249
4
1.5672
2
1.5320
4
1.5233
4
       
mPW1PW91 1.5396
4
1.5623
4
1.5623
4
1.5578
4
1.5263
4
1.5263
4
1.5284
4
1.5202
4
1.5202
4
1.5229
4
1.5674
2
1.5303
4
1.5217
4
  1.5610
2
1.5501
2
 
M06-2X 1.5660
2
1.5842
2
1.5842
2
1.5832
2
1.5335
5
1.5511
2
1.5518
2
1.5442
2
1.5442
2
1.5481
2
1.5640
2
1.5522
2
1.5454
2
  1.5560
2
1.5466
2
 
PBEPBE 1.5568
4
1.5740
4
1.5740
4
1.5703
4
1.5408
4
1.5408
4
1.5433
4
1.5339
4
1.5339
4
1.5373
4
1.5752
2
1.5444
4
1.5351
4
1.5116
2
1.5685
2
1.5572
2
1.5136
2
PBEPBEultrafine         1.5620
2
            1.5642
2
1.5554
2
  1.5684
2
1.5572
2
 
PBE1PBE 1.5720
2
1.5913
2
1.5913
2
1.5888
2
1.5381
5
1.5538
2
1.5544
2
1.5466
2
1.5466
2
1.5507
2
1.5673
2
1.5570
2
1.5484
2
  1.5609
2
1.5496
2
 
HSEh1PBE 1.5727
2
1.5913
2
1.5913
2
1.5890
2
1.5383
5
1.5539
2
1.5546
2
1.5467
2
1.5467
2
1.5507
2
1.5676
2
1.5570
2
1.5486
2
  1.6125
1
1.6000
1
 
TPSSh         1.4520
4
  1.4524
4
          1.4498
4
       
Moller Plesset perturbation MP2 1.5388
4
1.5661
4
1.5661
4
1.5681
4
1.5348
4
1.5348
4
1.5426
4
1.5389
4
1.5389
4
1.5314
4
1.5618
5
1.5440
4
1.5394
4
1.5350
4
1.5550
4
1.5407
4
1.5493
3
MP2=FULL 1.5388
4
1.5660
4
1.5660
4
1.5680
4
1.5327
4
1.5327
4
1.5405
4
1.5377
4
1.5377
4
1.5240
4
1.5623
2
1.5427
4
1.5310
4
1.5299
4
1.5597
2
1.5321
4
1.5420
3
ROMP2 1.5508
4
1.5875
4
1.5875
4
1.5830
4
1.5452
4
1.5452
4
1.5501
4
1.5485
4
1.5485
4
1.5415
4
1.5835
2
1.5571
4
1.5486
4
1.5277
2
1.5646
4
1.5309
2
1.5271
2
MP3         1.5383
4
  1.4480
5
                   
MP3=FULL         1.4467
5
  1.4431
5
                   
MP4   1.5758
4
    1.5411
4
      1.5455
4
  1.5758
2
1.5659
2
1.5451
4
  1.5822
2
1.5624
2
 
MP4=FULL   1.5884
2
    1.5573
2
      1.5551
2
    1.5643
2
1.5457
2
  1.5747
2
1.5505
2
 
B2PLYP         1.5474
5
              1.4456
3
       
Configuration interaction CID   1.5714
4
1.5714
4
1.5727
4
1.5296
4
    1.5326
4
                 
CISD   1.5844
4
1.5844
4
1.5854
4
1.5340
4
    1.5359
4
                 
Quadratic configuration interaction QCISD   1.5705
4
1.5705
4
1.5628
4
1.5145
4
1.5145
4
1.5640
3
1.5100
4
1.5100
4
1.5076
4
1.5832
2
1.5232
4
1.5094
4
  1.5801
2
1.6129
1
 
QCISD(T)         1.5598
4
          1.6148
2
1.5767
4
1.5523
4
  1.5804
4
1.5527
4
 
Coupled Cluster CCD   1.5752
4
1.5752
4
1.5776
4
1.5361
4
1.5361
4
1.5428
4
1.5390
4
1.5390
4
1.5306
4
1.5650
2
1.5462
4
1.5377
4
  1.5564
4
1.5385
4
 
CCSD         1.5433
4
          1.5805
2
1.5728
2
1.5533
2
1.5448
2
1.5813
2
1.5558
2
1.5460
2
CCSD=FULL         1.5591
2
          1.5789
2
1.5707
2
1.5382
2
1.5364
2
1.5706
2
1.5407
2
1.5371
2
CCSD(T)         1.5703
3
          1.5898
2
1.5424
4
1.5296
4
1.5242
4
1.5540
4
1.5335
4
1.5592
2
CCSD(T)=FULL         1.5299
4
          1.5886
2
1.5794
2
1.5501
2
1.5167
4
1.5830
2
1.5535
2
1.5504
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 1.5361
4
1.5010
4
1.5227
4
1.4927
4
1.5433
4
1.5429
4
density functional B3LYP 1.5706
4
1.5406
4
1.5592
4
1.5326
4
1.5701
4
1.5698
4
Moller Plesset perturbation MP2 1.5837
4
1.5492
4
1.5707
4
1.5426
4
1.5816
4
1.5804
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.