return to home page

III.G.1.a.

Comparison of levels of theory for Be-Cl


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 1.8639
4
PM3 1.7514
5
PM6 1.8436
5
composite G2 1.8402
5
G3 1.8402
5
G3B3 1.8375
5
G4 1.8381
5
CBS-Q 1.8460
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-pV(T+d)Z
hartree fock HF 1.8218
5
1.8855
5
1.8588
5
1.8952
5
1.8495
8
1.8404
5
1.8171
5
1.8264
5
1.8267
5
1.8403
5
1.8084
1
1.8358
5
1.8379
5
1.8221
4
1.8161
5
1.8290
4
1.8172
5
1.8128
5
1.8293
3
ROHF   1.8625
1
1.8377
1
  1.8171
1
1.8171
1
1.8150
1
1.8158
1
                     
density functional LSDA 1.8105
5
1.8358
5
1.8322
5
1.8579
5
1.8208
5
1.8208
5
1.8011
5
1.8030
5
1.8030
5
1.8186
5
  1.7929
2
1.8186
5
1.7979
5
1.7085
1
1.8081
5
1.7957
4
1.7086
1
 
SVWN   1.8490
5
    1.8208
5
1.7892
2
1.8011
5
1.7828
2
1.7828
2
1.7873
2
    1.7962
2
1.7855
2
  1.7940
2
1.7854
2
   
BLYP 1.8338
5
1.8771
5
1.8583
5
1.8896
5
1.8496
5
1.8496
5
1.8263
5
1.8317
5
1.8317
5
1.8473
5
  1.8178
2
1.8436
5
1.8258
4
  1.8280
1
     
B1B95 1.8232
5
1.8495
5
1.8455
5
1.8748
5
1.8333
5
1.8336
5
1.8118
5
1.8183
5
1.8183
5
1.8327
5
  1.8014
2
1.8302
5
1.8140
4
1.7121
1
1.8198
5
1.8098
4
1.7122
1
 
B3LYP 1.8243
5
1.8682
5
1.8481
5
1.8794
5
1.8377
5
1.8377
5
1.8160
5
1.8213
5
1.8243
4
1.8359
5
1.8019
1
1.8329
5
1.8334
5
1.8163
4
1.8104
5
1.8242
4
1.8114
5
1.8070
5
1.8225
3
B3LYPultrafine         1.8378
5
              1.8092
2
1.8000
2
  1.8077
2
1.8253
5
   
B3PW91 1.8304
4
1.8691
5
1.8491
5
1.8776
5
1.8352
5
1.8352
5
1.8147
5
1.8199
5
1.8228
4
1.8341
5
  1.8056
2
1.8366
4
1.8165
4
  1.8180
1
     
mPW1PW91 1.8278
4
1.8667
5
1.8508
4
1.8750
5
1.8325
5
1.8325
5
1.8122
5
1.8173
5
1.8174
5
1.8314
5
  1.8034
2
1.8339
4
1.8140
4
  1.8085
3
1.7972
2
   
M06-2X 1.7810
2
1.8177
2
1.8006
2
1.8222
2
1.8341
5
1.7968
2
1.7962
2
1.7918
2
1.7918
2
1.7973
2
  1.8021
2
1.8044
2
1.7947
2
  1.8033
2
1.7947
2
   
PBEPBE 1.8348
4
1.8724
5
1.8585
4
1.8880
4
1.8418
5
1.8418
5
1.8202
5
1.8257
5
1.8257
5
1.8400
5
1.8061
1
1.8115
2
1.8384
5
1.8188
5
1.7218
1
1.8114
2
1.8040
2
1.7219
1
 
PBEPBEultrafine         1.8101
3
              1.8130
2
1.8037
2
  1.8115
2
1.8040
2
   
PBE1PBE 1.7844
2
1.8030
2
1.8030
2
1.8217
2
1.8315
5
1.7977
2
1.7972
2
1.7938
2
1.7938
2
1.7970
2
  1.8028
2
1.8050
2
1.7963
2
  1.8036
2
1.7965
2
   
HSEh1PBE 1.7847
2
1.8201
2
1.8034
2
1.8224
2
1.8323
5
1.7985
2
1.7977
2
1.7942
2
1.7942
2
1.7974
2
  1.8034
2
1.8054
2
1.7968
2
  1.8040
2
1.7969
2
   
TPSSh         1.8281
5
  1.8182
5
            1.8172
5
         
Moller Plesset perturbation MP2 1.8283
4
1.8880
5
1.8496
5
1.9006
5
1.8174
5
1.8174
5
1.7991
5
1.8110
5
1.8112
5
1.8327
5
  1.8312
5
1.8313
5
1.8202
4
1.8014
3
1.8339
5
1.8178
5
1.8021
3
1.8268
3
MP2=FULL 1.8281
4
1.8879
5
1.8534
4
1.9084
4
1.8132
5
1.8132
5
1.7952
5
1.8084
5
1.8104
4
1.8271
4
  1.8080
2
1.8318
4
1.8078
4
1.7914
3
1.8181
3
1.7984
2
1.7891
2
1.8120
3
MP3         1.8164
5
  1.8157
5
                       
MP3=FULL         1.8131
5
  1.8021
5
                       
MP4   1.9002
4
    1.8198
5
    1.8040
1
1.8175
4
    1.8134
2
1.8135
2
1.8085
3
  1.8204
2
1.8080
2
   
MP4=FULL   1.8401
2
    1.7890
2
      1.7919
2
      1.8110
2
1.7955
2
  1.8167
2
1.8000
2
   
B2PLYP         1.8494
3
                1.8440
3
         
Configuration interaction CID   1.8973
4
1.8569
4
1.9141
4
1.8198
5
    1.8129
5
                     
CISD   1.8987
4
1.8580
4
1.9155
4
1.8207
5
    1.8165
4
                     
Quadratic configuration interaction QCISD   1.8954
5
1.8611
4
1.9201
4
1.8215
5
1.8268
4
1.8031
5
1.8155
5
1.8156
5
1.8422
4
  1.8125
2
1.8361
5
1.8220
5
  1.8190
2
1.8062
2
   
QCISD(T)         1.8211
5
    1.8053
1
      1.8140
2
1.8402
4
1.8251
4
  1.8419
4
1.8241
4
   
Coupled Cluster CCD   1.8995
4
1.8588
4
1.9171
4
1.8200
5
1.8253
4
1.8023
4
1.8135
5
1.8165
4
1.8410
4
  1.8109
2
1.8341
5
1.8234
4
  1.8386
4
1.8210
4
   
CCSD         1.8209
5
    1.8036
1
      1.8120
2
1.8123
2
1.8049
2
  1.8184
2
1.8059
2
   
CCSD=FULL         1.7885
2
            1.8105
2
1.8099
2
1.7942
2
  1.8147
2
1.7985
2
   
CCSD(T)         1.7955
3
1.8007
1
  1.8049
1
    1.8071
1
1.8137
2
1.8359
5
1.8224
5
  1.8397
5
1.8222
5
   
CCSD(T)=FULL         1.8168
5
            1.8121
2
1.7954
4
1.7777
4
  1.8019
4
1.7810
4
   

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 1.8826
5
1.8328
5
1.8768
5
1.8264
5
1.8862
5
1.8888
5
density functional B1B95 1.8708
1
1.8249
1
       
B3LYP 1.8859
5
1.8413
5
1.8780
5
1.8342
5
1.8797
5
1.8776
5
Moller Plesset perturbation MP2 1.8955
5
1.8274
5
1.8827
5
1.8183
5
1.8856
5
1.8903
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.