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III.G.1.a.

Comparison of levels of theory for P-Br


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 2.1009
3
PM3 2.1499
3
PM6 2.1950
3
composite G2 2.2196
3
G3 2.2311
3
G3B3 2.2786
3
G4 2.2642
3
CBS-Q 2.2041
3

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 2.2302
3
2.3861
3
2.1996
3
2.3322
3
2.2191
3
2.2191
3
2.2200
3
2.2324
3
2.2324
3
2.2030
3
2.2366
3
2.2398
3
2.2254
3
2.2214
3
2.2422
3
2.2260
3
2.2214
3
density functional LSDA 2.2597
3
2.1906
3
2.1906
3
2.3356
3
2.2206
3
2.2206
3
2.2210
3
2.2393
3
2.2393
3
2.1965
3
2.2376
3
2.2413
3
2.2233
3
  2.2423
3
2.2232
3
 
SVWN   2.3781
3
    2.2206
3
2.2206
3
2.2210
3
2.2393
3
2.2393
3
2.1965
3
  2.2413
3
2.2233
3
  2.2423
3
2.2232
3
 
BLYP 2.3041
3
2.4472
3
2.2529
3
2.4051
3
2.2845
3
2.2845
3
2.2872
3
2.3098
3
2.3098
3
2.2632
3
2.3085
3
2.3084
3
2.2932
3
       
B1B95 2.2555
3
2.1951
3
2.1951
3
2.3370
3
2.2192
3
2.2192
3
2.2196
3
2.2372
3
2.2372
3
2.1999
3
2.2366
3
2.2399
3
2.2244
3
  2.2415
3
2.2248
3
 
B3LYP 2.2777
3
2.4144
3
2.2245
3
2.3695
3
2.2529
3
2.2529
3
2.2545
3
2.2730
3
2.2730
3
2.2325
3
2.2728
3
2.2745
3
2.2593
3
2.2548
3
2.2762
3
2.2597
3
2.2548
3
B3LYPultrafine         2.2527
3
            2.2745
3
2.2592
3
  2.2762
3
2.2596
3
 
B3PW91 2.2667
3
2.3972
3
2.2085
3
2.3509
3
2.2338
3
2.2338
3
2.2343
3
2.2517
3
2.2517
3
2.2136
3
2.2515
3
2.2544
3
2.2389
3
       
mPW1PW91 2.2596
3
2.3891
3
2.2021
3
2.3427
3
2.2264
3
2.2264
3
2.2269
3
2.2436
3
2.2436
3
2.2065
3
2.2437
3
2.2467
3
2.2315
3
  2.2484
3
2.2320
3
 
M06-2X 2.2466
3
2.3869
3
2.2070
3
2.3341
3
2.2242
3
2.2242
3
2.2243
3
2.2415
3
2.2415
3
2.2066
3
2.2436
3
2.2438
3
2.2316
3
  2.2462
3
2.2320
3
 
PBEPBE 2.2827
3
2.4178
3
2.2249
3
2.3732
3
2.2520
3
2.2520
3
2.2534
3
2.2745
3
2.2745
3
2.2312
3
2.2730
3
2.2742
3
2.2587
3
  2.2756
3
2.2591
3
 
PBEPBEultrafine         2.2519
3
            2.2742
3
2.2587
3
  2.2756
3
2.2590
3
 
PBE1PBE 2.2567
3
2.2003
3
2.2003
3
2.3410
3
2.2241
3
2.2241
3
2.2244
3
2.2416
3
2.2416
3
2.2043
3
2.2417
3
2.2445
3
2.2295
3
  2.2462
3
2.2300
3
 
HSEh1PBE 2.2585
3
2.3916
3
2.2032
3
2.3454
3
2.2274
3
2.2274
3
2.2280
3
2.2457
3
2.2457
3
2.2075
3
2.2457
3
2.2482
3
2.2333
3
  2.2499
3
2.2338
3
 
TPSSh         2.2429
3
  2.2419
3
          2.2482
3
       
Moller Plesset perturbation MP2 2.2620
3
2.4341
3
2.2039
3
2.3870
3
2.2390
3
2.2339
3
2.2344
3
2.2397
3
2.2397
3
2.2018
3
2.2417
3
2.2495
3
2.2208
3
2.2068
3
2.2564
3
2.2200
3
2.2051
3
MP2=FULL 2.2617
3
2.4347
3
2.2021
3
2.3870
3
2.2327
3
2.2293
3
2.2300
3
2.2364
3
2.2364
3
2.1838
3
2.2412
3
2.2479
3
2.2100
3
2.2020
3
2.2550
3
2.2063
3
2.1985
3
MP3         2.2411
3
  2.2485
3
                   
MP3=FULL         2.2427
3
  2.2422
3
                   
MP4   2.4547
3
    2.2465
3
      2.2558
3
  2.2584
3
2.2654
3
2.2365
3
       
MP4=FULL   2.4552
3
    2.2417
3
      2.2537
3
    2.2637
3
2.2285
3
  2.2715
3
   
Configuration interaction CID   2.4245
3
2.2014
3
2.3755
3
2.2284
3
    2.2351
3
                 
CISD   2.4269
3
2.2020
3
2.3778
3
2.2289
3
    2.2359
3
                 
Quadratic configuration interaction QCISD   2.4522
3
2.2134
3
2.4019
3
2.2431
3
2.2431
3
2.2440
3
2.2508
3
2.2508
3
2.2117
3
2.2534
3
2.2608
3
2.2313
3
  2.2663
3
2.2296
3
 
QCISD(T)         2.2476
3
          2.2602
3
2.2666
3
2.2369
3
  2.2731
3
2.2364
3
 
Coupled Cluster CCD   2.4451
3
2.2106
3
2.3950
3
2.2403
3
2.2403
3
2.2410
3
2.2470
3
2.2470
3
2.2089
3
2.2495
3
2.2570
3
2.2281
3
  2.2622
3
2.2266
3
 
CCSD         2.2420
3
          2.2521
3
2.2593
3
2.2301
3
  2.2646
3
2.2284
3
 
CCSD=FULL         2.2373
3
            2.2577
3
2.2221
3
       
CCSD(T)         2.2468
3
          2.2593
3
2.2657
3
2.2367
3
  2.2720
3
2.2350
3
 
CCSD(T)=FULL         2.2419
3
          2.2587
3
2.2641
3
    2.2707
3
2.2217
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 2.3494
3
  2.3514
3
  2.3986
3
2.3653
3
density functional B3LYP 2.4043
3
  2.4041
3
  2.4432
3
2.4113
3
Moller Plesset perturbation MP2 2.4160
3
  2.4169
3
  2.4545
3
2.4279
3
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.