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III.G.1.a.

Comparison of levels of theory for Cl-Al


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 1.9680
3
PM3 2.0694
8
PM6 2.0736
9
composite G2 2.1103
9
G3 2.1103
9
G3B3 2.1204
9
G4 2.1115
9
CBS-Q 2.1093
9

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 aug-cc-pV(T+d)Z
hartree fock HF 2.1123
9
2.2070
9
2.1065
9
2.2140
9
2.0993
23
2.1103
9
2.1071
9
2.1043
9
2.1043
9
2.1028
9
2.0650
6
2.1193
10
2.1332
9
2.1080
9
2.1492
1
2.1338
9
2.1033
9
2.1494
1
2.1020
9
2.1505
1
ROHF         2.1880
2
                             
density functional LSDA 2.1014
9
2.1443
9
2.0919
9
2.1888
9
2.0980
9
2.0980
9
2.0958
9
2.0922
9
2.0922
9
2.0686
7
  2.1519
1
2.1199
9
2.0940
9
  2.1182
9
2.1420
3
  2.1350
1
2.1350
1
SVWN   2.1804
9
2.1388
1
2.2588
1
2.0980
9
2.1484
1
2.0958
9
2.1464
1
2.1464
1
2.1348
1
  2.1519
1
2.1741
1
2.1441
1
2.1353
1
2.1818
1
2.1441
1
2.1353
1
2.1350
1
2.1350
1
BLYP 2.1392
9
2.2204
9
2.1298
9
2.2342
9
2.1392
9
2.1392
9
2.1378
9
2.1365
9
2.1365
9
2.1285
9
  2.1968
1
2.1600
9
2.1365
9
  2.1225
6
    2.1802
1
2.1813
1
B1B95 2.1141
9
2.1542
9
2.1018
9
2.2005
9
2.1052
9
2.1064
9
2.1130
8
2.1013
9
2.1013
9
2.0988
9
  2.1600
1
2.1288
9
2.1039
9
  2.1344
8
2.2166
2
  2.1463
1
2.1467
1
B3LYP 2.1246
9
2.2057
9
2.1131
9
2.2167
9
2.1210
9
2.1209
9
2.1191
9
2.1170
9
2.1922
3
2.1109
9
2.0735
6
2.1295
10
2.1421
9
2.1182
9
2.1620
1
2.1410
9
2.1129
9
2.1623
1
2.1105
9
2.1622
1
B3LYPultrafine         2.1210
9
  2.0806
3
        2.1771
1
2.1972
1
2.0956
7
  2.2071
1
2.1136
9
  2.1608
1
2.1622
1
B3PW91 2.2209
3
2.2006
9
2.1080
9
2.2080
9
2.1123
9
2.1123
9
2.1098
9
2.1066
9
2.1757
3
2.1039
9
  2.1671
1
2.1347
9
2.1097
9
  2.1002
6
    2.1517
1
2.1521
1
mPW1PW91 2.2166
3
2.1967
9
2.1668
3
2.2036
9
2.1079
9
2.1079
9
2.1054
9
2.1022
9
2.1022
9
2.0996
9
  2.1622
1
2.1304
9
2.1054
9
  2.1104
7
2.1557
1
  2.1471
1
2.1475
1
M06-2X 2.1609
1
2.2582
1
2.1479
1
2.2773
1
2.1051
9
2.1593
1
2.1608
1
2.1572
1
2.1572
1
2.1479
1
  2.1631
1
2.1851
1
2.1560
1
  2.1941
1
2.1568
1
  2.1488
1
2.1495
1
PBEPBE 2.2259
3
2.2093
9
2.1834
3
2.3090
3
2.1249
9
2.1249
9
2.1231
9
2.1205
9
2.1204
9
2.1153
9
2.0785
6
2.1800
1
2.1467
9
2.1223
9
  2.2104
1
2.1006
7
  2.1643
1
2.1649
1
PBEPBEultrafine         2.0976
13
            2.1796
1
2.2011
1
2.1722
1
  2.2098
1
2.1729
1
  2.1643
1
2.1649
1
PBE1PBE 2.1590
1
2.1500
1
2.1500
1
2.2752
1
2.1127
10
2.1575
1
2.1600
1
2.1558
1
2.1558
1
2.1462
1
  2.1618
1
2.1854
1
2.1547
1
  2.1934
1
2.1553
1
  2.1467
1
2.1472
1
HSEh1PBE 2.1600
1
2.2655
1
2.1516
1
2.2776
1
2.1091
9
2.1600
1
2.1620
1
2.1581
1
2.1581
1
2.1478
1
  2.1639
1
2.1872
1
2.1565
1
  2.1952
1
2.1572
1
  2.1484
1
2.1489
1
TPSSh   2.2682
1
2.1566
1
2.2782
1
2.2008
9
2.1631
1
2.2003
9
2.1608
1
      2.1678
1
2.1909
1
2.2001
9
  2.1984
1
2.1600
1
  2.1526
1
2.1531
1
Moller Plesset perturbation MP2 2.2329
3
2.2202
9
2.0939
9
2.2316
9
2.0978
9
2.0978
9
2.0808
21
2.0928
9
2.0928
9
2.1007
9
  2.1105
10
2.1314
9
2.1078
9
2.1440
1
2.1431
9
2.1594
3
2.1459
1
2.1016
9
2.1510
1
MP2=FULL 2.2324
3
2.2203
9
2.1454
3
2.3286
3
2.0947
9
2.0947
9
2.0921
9
2.0911
9
2.1504
3
2.1458
3
  2.1483
1
2.1290
9
2.1593
3
2.1102
1
2.1198
7
2.1458
1
2.1012
1
2.0905
9
2.1363
1
MP3         2.0977
9
  2.1930
9
        2.1473
1
2.1778
1
2.1511
1
        2.1445
1
2.1498
1
MP3=FULL         2.1914
9
  2.1909
9
        2.1477
1
2.1757
1
2.1450
1
        2.1375
1
2.1373
1
MP4   2.3213
3
    2.1022
9
      2.1562
3
    2.1508
1
2.1820
1
2.0953
2
  2.2109
1
2.1615
1
  2.1478
1
2.1541
1
MP4=FULL   2.2961
1
    2.1382
1
2.1382
1
2.1412
1
2.1375
1
2.1375
1
2.1353
1
  2.1509
1
2.1797
1
2.1480
1
  2.2074
1
2.1496
1
  2.1399
1
2.1409
1
B2PLYP 2.1637
1
2.2758
1
2.1466
1
2.2916
1
2.1098
9
2.1568
1
2.1600
1
2.1568
1
2.1568
1
2.1510
1
  2.1641
1
2.1882
1
2.1710
9
  2.2046
1
2.1636
1
  2.1528
1
2.1556
1
B2PLYP=FULL 2.1635
1
2.2758
1
2.1459
1
2.2916
1
2.1559
1
2.1559
1
2.1600
1
2.1564
1
2.1564
1
2.1477
1
  2.1639
1
2.1874
1
2.1583
1
  2.2035
1
2.1600
1
  2.1499
1
2.1512
1
B2PLYP=FULLultrafine         2.0779
6
                             
Configuration interaction CID   2.3210
3
2.1519
3
2.3442
3
2.0988
9
    2.1546
3
                    2.1440
1
2.1478
1
CISD   2.3237
3
2.1536
3
2.3471
3
2.0996
9
    2.1561
3
                    2.1445
1
2.1483
1
Quadratic configuration interaction QCISD   2.2290
9
2.1538
3
2.3520
3
2.1020
9
2.1602
3
2.1550
3
2.0957
9
2.0957
9
2.1617
3
  2.1515
1
2.2053
3
2.1709
3
  2.2088
1
2.1590
1
  2.1467
1
2.1513
1
QCISD(T)         2.1607
3
            2.1517
1
2.2062
3
2.1716
3
  2.2212
3
2.1666
3
  2.1479
1
2.1538
1
Coupled Cluster CCD   2.3232
3
2.1508
3
2.3470
3
2.0997
9
2.1573
3
2.1517
3
2.1540
3
2.1540
3
2.1600
3
  2.1497
1
2.2021
3
2.1695
3
  2.2156
3
2.1619
3
  2.1454
1
2.1501
1
CCSD         2.1012
9
            2.1507
1
2.1815
1
2.1529
1
2.1429
1
2.2077
1
2.1577
1
2.1448
1
2.1461
1
2.1507
1
CCSD=FULL         2.1379
1
            2.1508
1
2.1793
1
2.1465
1
2.1099
1
2.2042
1
2.1461
1
2.1011
1
2.1380
1
2.1370
1
CCSD(T)         2.1028
9
            2.1511
1
2.2054
3
2.1712
3
2.1447
1
2.2202
3
2.1657
3
2.1471
1
2.1475
1
2.1533
1
CCSD(T)=FULL         2.1576
3
            2.1511
1
2.1803
1
2.1477
1
2.1110
1
2.2067
1
2.1488
1
2.1024
1
2.1394
1
2.1399
1

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 2.2111
9
2.1149
9
2.2145
9
2.1149
9
2.2042
9
2.1936
9
density functional B1B95 2.1683
6
2.0926
6
       
B3LYP 2.2247
9
2.1305
9
2.2250
9
2.1305
9
2.2165
9
2.2022
9
Moller Plesset perturbation MP2 2.2324
9
2.1129
9
2.2339
9
2.1096
9
2.2175
9
2.2069
9
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.