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III.G.1.a.

Comparison of levels of theory for Si-P


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 1.7416
4
PM3 1.6288
4
PM6 1.9212
5
composite G2 2.0922
4
G3 2.0922
4
G3B3 2.1330
4
G4 2.0925
4
CBS-Q 2.0922
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 2.0432
4
2.1431
3
2.0797
4
2.2074
4
2.1163
5
2.0922
4
2.0938
4
2.0904
4
2.0904
4
2.0875
4
2.0968
4
2.1025
4
2.0909
4
2.0871
4
2.1085
4
2.0929
4
2.0878
4
ROHF 2.0065
3
2.1646
3
2.0416
3
2.1565
3
2.0534
3
2.0534
3
2.0553
3
2.0515
3
2.0515
3
2.0465
3
  2.0615
3
2.0501
3
2.0461
3
2.0674
3
2.0524
3
2.0471
3
density functional LSDA 2.0860
4
2.1816
4
2.1127
4
2.2146
4
2.1292
4
2.1292
4
2.1295
4
2.1224
4
2.1224
4
2.1169
4
  2.1358
4
2.1182
4
2.0688
3
2.1375
4
2.1187
4
2.0688
3
SVWN   2.2180
4
    2.0851
3
  2.1295
4
                   
BLYP 2.0812
4
2.2582
4
2.1438
4
2.2534
4
2.1634
4
2.1634
4
2.1640
4
2.1595
4
2.1595
4
2.1502
4
  2.1685
4
2.1519
4
       
B1B95 2.0700
4
2.0992
4
2.0992
4
2.2023
4
2.1127
4
2.1127
4
2.0742
3
2.1095
4
2.1095
4
2.1056
4
  2.1215
4
2.1079
4
2.1034
4
2.1242
4
2.1089
4
2.1036
4
B3LYP 2.0847
4
2.2285
4
2.1158
4
2.2241
4
2.1330
4
2.1330
4
2.1337
4
2.1287
4
2.1287
4
2.1222
4
2.1316
4
2.1395
4
2.1242
4
2.1193
4
2.1421
4
2.1253
4
2.1197
4
B3LYPultrafine         2.1330
4
                    2.1533
3
 
B3PW91 2.0794
4
2.2198
4
2.1093
4
2.2128
4
2.1231
4
2.1231
4
2.1237
4
2.1190
4
2.1190
4
2.1142
4
  2.1311
4
2.1167
4
       
mPW1PW91 2.0735
4
2.2139
4
2.1036
4
2.2072
4
2.1170
4
2.1170
4
2.1176
4
2.1132
4
2.1132
4
2.1087
4
  2.1252
4
2.1113
4
       
M06-2X         2.1055
4
                       
PBEPBE 2.0702
4
2.2432
4
2.1326
4
2.2362
4
2.1480
4
2.1480
4
2.1485
4
2.1448
4
2.1448
4
2.1372
4
  2.1545
4
2.1395
4
2.1352
4
2.2935
1
2.2758
1
2.1354
4
PBE1PBE         2.1174
4
                       
HSEh1PBE         2.1196
4
                       
TPSSh         2.0762
4
  2.0761
4
          2.0721
4
       
Moller Plesset perturbation MP2 2.0878
4
2.2499
4
2.1035
4
2.2418
4
2.1183
4
2.1183
4
2.1188
4
2.1128
4
2.1128
4
2.1186
4
2.1244
4
2.1400
4
2.1199
4
  2.1468
4
2.1222
4
 
MP2=FULL 2.0871
4
2.2504
4
2.1007
4
2.2418
4
2.1155
4
2.1155
4
2.1163
4
2.1121
4
2.1121
4
2.1073
4
  2.1373
4
2.1122
4
  2.2602
1
2.1105
4
 
ROMP2 2.0574
3
2.2061
3
2.0680
3
2.2022
3
2.0823
3
2.0823
3
2.0829
3
2.0770
3
2.0770
3
2.0812
3
  2.1021
3
2.0821
3
2.0732
3
2.1086
3
2.0844
3
2.0748
3
MP3         2.1074
4
  2.0464
4
                   
MP3=FULL         2.0446
4
  2.0451
4
                   
MP4   2.2772
4
    2.1331
4
      2.1280
4
      2.0951
3
       
B2PLYP         2.1288
4
              2.0727
4
       
Configuration interaction CID   2.2331
4
2.0883
4
2.2255
4
2.1027
4
    2.0973
4
                 
CISD   2.2546
4
2.0941
4
2.2428
4
2.1090
4
    2.1038
4
                 
Quadratic configuration interaction QCISD   2.3753
3
2.1075
4
2.2807
4
2.1245
4
2.1245
4
2.1253
4
2.1192
4
2.1192
4
2.1195
4
  2.1464
4
2.1194
4
       
QCISD(T)         2.1335
4
            2.1584
4
2.1315
4
  2.1641
4
2.1335
4
 
Coupled Cluster CCD   2.2417
4
2.0935
4
2.2342
4
2.1087
4
2.1087
4
2.1095
4
2.1029
4
2.1029
4
2.1081
4
  2.1316
4
2.1086
4
  2.1382
4
2.0760
3
 
CCSD         2.1184
4
                       
CCSD(T)                       2.1552
4
2.1290
4
2.0843
3
2.1611
4
2.1717
3
2.0853
3
CCSD(T)=FULL         2.0905
3
                2.0794
3
    2.0789
3

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 2.2215
4
2.1118
4
2.2225
4
2.1076
4
2.2643
4
2.1422
3
density functional B3LYP 2.2479
4
2.1535
4
2.2476
4
2.1508
4
2.2508
4
2.2319
4
Moller Plesset perturbation MP2 2.2616
4
2.1489
4
2.2575
4
2.1428
4
2.2577
4
2.2473
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.