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You are here: Calculated > Geometry > Calculated geometry > One type of bond

Comparison of levels of theory for Se-Se


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 PM3 2.1906
5
PM6 2.2452
5
composite G2 2.1816
5
G3 2.2406
2
G3B3 2.2531
5
G3MP2 2.1505
1
G4 2.2437
5
CBS-Q 2.1841
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 daug-cc-pVDZ daug-cc-pVTZ
hartree fock HF 2.1982
5
2.3168
5
2.1808
5
2.2732
5
2.1816
5
2.1817
5
2.1835
5
2.1943
5
2.1948
5
2.1416
5
2.2322
2
2.1962
5
2.1903
5
2.1842
5
2.1819
5
2.1934
5
2.1843
5
2.1816
5
2.1384
1
2.2448
2
2.1844
5
ROHF 2.1528
1
2.2634
1
2.1375
1
2.2160
1
2.1985
2
2.1370
1
2.1388
1
2.1466
1
2.1466
1
2.0997
1
2.1338
1
2.1472
1
2.1418
1
2.1360
1
2.1336
1
2.1442
1
2.1360
1
2.1334
1
2.1360
1
2.1446
1
2.1359
1
density functional LSDA 2.2088
4
2.1966
2
2.1309
2
2.2691
4
2.1804
4
2.1804
4
2.1804
4
2.1883
4
2.1883
4
2.1339
4
    2.1910
3
2.1763
4
2.1841
2
2.1874
4
2.1785
3
2.1829
2
2.1663
1
   
BLYP 2.2735
5
2.3739
4
2.2490
5
2.3653
5
2.2814
5
2.2915
4
2.2639
5
2.3080
4
2.3089
4
2.2110
5
2.3045
2
2.3198
2
2.2762
5
2.2655
5
  2.3180
2
2.3063
2
  2.2215
1
2.3182
2
2.3063
2
B1B95 2.2291
5
2.2275
2
2.1941
5
2.2965
5
2.1984
5
2.1984
5
2.1995
5
2.2122
5
2.2127
5
2.1545
5
2.2398
2
2.2536
2
2.2096
5
2.2019
5
2.1732
3
2.2102
5
2.2015
5
2.2170
2
2.1605
1
2.2518
2
2.2423
2
B3LYP 2.2488
5
2.3610
5
2.2207
5
2.3284
5
2.2300
5
2.2302
5
2.2314
5
2.2429
5
2.2435
5
2.1818
5
2.2721
2
2.2444
5
2.2415
5
2.2315
5
2.2295
5
2.2420
5
2.2310
5
2.2288
5
2.1883
1
2.2854
2
2.2740
2
B3LYPultrafine   2.4052
2
    2.2300
5
2.2674
2
2.2712
2
2.2838
2
  2.2171
2
2.2721
2
2.2865
2
2.2828
2
2.2735
2
  2.2852
2
2.2369
5
  2.1883
1
2.2854
2
2.2740
2
B3PW91 2.2401
5
2.3472
5
2.2058
5
2.3096
5
2.2110
5
2.2113
5
2.2122
5
2.2234
5
2.2239
5
2.1655
5
2.2513
2
2.2649
2
2.2221
5
2.2127
5
  2.2642
2
2.2532
2
  2.1706
1
2.2644
2
2.2533
2
mPW1PW91 2.2337
5
2.3401
5
2.1996
5
2.3015
5
2.2037
5
2.2040
5
2.2048
5
2.2160
5
2.2165
5
2.1592
5
2.2443
2
2.2580
2
2.2142
5
2.2056
5
  2.2570
2
2.2465
2
  2.1640
1
2.2574
2
2.2465
2
M06-2X 2.2562
2
2.3892
2
2.2037
5
2.3389
2
2.1957
5
2.2356
2
2.2385
2
2.2529
2
2.2540
2
2.1934
2
2.1995
5
2.2614
2
2.2512
2
2.2484
2
  2.2542
2
2.2489
2
  2.1644
1
2.2546
2
2.2488
2
PBEPBE 2.2561
5
2.3711
5
2.2254
5
2.3374
5
2.2326
5
2.2330
5
2.2338
5
2.2561
4
2.2568
4
2.1845
5
2.2718
2
2.2863
2
2.2453
5
2.2362
5
2.2154
2
2.2592
3
2.2490
3
2.2139
2
2.1951
1
2.2848
2
2.2743
2
PBEPBEultrafine   2.4102
2
    2.2648
2
2.2656
2
2.2693
2
2.2828
2
  2.2157
2
2.2718
2
2.2863
2
2.2819
2
2.2735
2
  2.2845
2
2.2742
2
  2.1951
1
2.2848
2
2.2743
2
PBE1PBE 2.2681
2
2.2324
2
2.2324
2
2.3467
2
2.2022
5
2.2378
2
2.2414
2
2.2541
2
2.2554
2
2.1919
2
2.2429
2
2.2568
2
2.2525
2
2.2447
2
  2.2552
2
2.2453
2
  2.1633
1
2.2553
2
2.2453
2
HSEh1PBE 2.2694
2
2.3526
4
2.2351
2
2.3519
2
2.2148
4
2.2423
2
2.2162
4
2.2583
2
2.2597
2
2.1952
2
2.2470
2
2.2611
2
2.2572
2
2.2186
4
  2.2597
2
2.2496
2
  2.1672
1
2.2599
2
2.2496
2
TPSSh 2.2820
2
2.3983
2
2.2431
2
2.3608
2
2.2401
5
2.2491
2
2.2412
5
2.2656
2
2.2670
2
2.2031
5
2.2536
2
2.2686
2
2.2648
2
2.2446
5
2.2541
2
2.2670
2
2.2565
2
2.2538
2
2.1754
1
2.2672
2
2.2565
2
wB97X-D 2.2643
2
2.3721
2
2.2231
5
2.3371
2
2.2253
5
2.2374
2
2.2271
5
2.2526
2
2.2392
5
2.1919
2
2.2416
2
2.2412
5
2.2313
5
2.2305
5
2.2427
2
2.2537
2
2.2303
5
2.2427
2
2.1589
1
2.2539
2
2.2446
2
B97D3 2.3022
2
2.3765
5
2.2625
2
2.3870
2
2.2407
5
2.2758
2
2.2423
5
2.2950
2
2.2575
5
2.2231
2
2.2418
5
2.2577
5
2.2918
2
2.2430
5
2.2809
2
2.2952
2
2.2424
5
2.2807
2
2.2009
1
2.2954
2
2.2423
5
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 daug-cc-pVDZ daug-cc-pVTZ
Moller Plesset perturbation MP2 2.2761
5
2.4462
5
2.2318
5
2.4062
5
2.2579
5
2.2436
5
2.2450
5
2.2702
5
2.2566
5
2.1790
5
2.2567
2
2.2456
5
2.2437
5
2.2462
2
2.2320
2
2.2504
5
2.2468
2
2.2305
2
2.1727
1
2.2791
2
2.2461
2
MP2=FULL 2.2759
5
2.4468
5
2.2301
5
2.4070
5
2.2365
5
2.2362
5
2.2377
5
2.2504
5
2.2505
5
2.1608
5
2.2440
2
2.2730
2
2.2416
5
2.2397
2
2.2292
2
2.2591
3
2.2348
2
2.2267
2
2.1676
1
2.2781
2
2.2339
2
ROMP2 2.2218
1
2.1944
1
2.1944
1
2.3535
1
2.2066
1
2.2065
1
2.2100
1
2.2187
1
2.2187
1
2.1465
1
2.1939
1
2.2073
1
2.2025
1
2.1829
1
  2.2145
1
    2.1829
1
2.2153
1
2.1834
1
MP3         2.2128
3
  2.2395
4
                      2.1688
1
   
MP3=FULL         2.2341
4
  2.2350
4
                      2.1654
1
   
MP4   2.3979
4
    2.2261
4
      2.2389
4
2.1465
1
      2.2057
3
        2.1850
1
   
MP4=FULL                                     2.1799
1
   
B2PLYP 2.2855
2
2.4203
2
2.2540
2
2.3869
2
2.2344
5
2.2655
2
2.2694
2
2.2823
2
2.2833
2
2.2115
2
2.2663
2
2.2809
2
2.2768
2
2.2529
5
  2.2824
2
2.2648
2
  2.1851
1
2.2827
2
2.2646
2
B2PLYP=FULL 2.2854
2
2.4204
2
2.2534
2
2.3869
2
2.2629
2
2.2630
2
2.2669
2
2.2805
2
2.2815
2
2.2060
2
2.2624
2
2.2813
2
2.2761
2
2.2620
2
  2.2820
2
2.2611
2
  2.1836
1
2.2824
2
2.2608
2
B2PLYP=FULLultrafine 2.2854
2
2.4204
2
2.2534
2
2.3869
2
2.2322
5
2.2630
2
2.2669
2
2.2805
2
2.2815
2
2.2060
2
2.2624
2
2.2813
2
2.2419
5
2.2273
5
  2.2820
2
2.2254
5
  2.1836
1
2.2824
2
2.2608
2
Configuration interaction CID   2.3864
5
2.2092
5
2.3455
5
2.2187
5
    2.2281
5
    2.2448
2
  2.2595
2
2.2349
2
        2.1487
1
2.2657
2
2.2339
2
CISD   2.3900
5
2.2105
5
2.3495
5
2.2202
5
    2.2301
5
    2.2462
2
  2.2610
2
2.2358
2
        2.1501
1
2.2670
2
2.2347
2
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 daug-cc-pVDZ daug-cc-pVTZ
Quadratic configuration interaction QCISD 2.2197
1
2.4136
5
2.2253
5
2.3730
5
2.2357
5
2.2355
5
2.2374
5
2.2474
5
2.2475
5
2.1754
5
2.2597
2
2.2760
2
2.2369
5
2.2140
5
  2.2821
2
2.2512
2
  2.1674
1
2.2826
2
2.2508
2
QCISD(T)         2.2484
5
    2.2934
2
    2.2690
2
2.2854
2
2.2504
5
2.2283
5
  2.2579
5
2.2411
3
  2.1809
1
2.2928
2
2.2613
2
QCISD(T)=FULL         2.2699
2
  2.2733
2
      2.2594
2
  2.2799
2
2.2543
2
2.2430
2
2.2913
2
2.2503
2
2.1632
1
2.1761
1
2.2920
2
2.2494
2
Coupled Cluster CCD 2.2190
1
2.4070
5
2.2222
5
2.3660
5
2.2323
5
2.2321
5
2.2335
5
2.2429
5
2.2429
5
2.1718
5
2.2562
2
2.2722
2
2.2329
5
2.2095
5
  2.2384
5
2.2479
2
  2.1624
1
2.2790
2
2.2475
2
CCSD         2.2349
5
2.2681
2
2.2718
2
2.2832
2
2.2834
2
2.2075
2
2.2592
2
2.2753
2
2.2728
2
2.2509
2
2.2355
2
2.2815
2
2.2508
2
2.2342
2
2.1664
1
2.2820
2
2.2503
2
CCSD=FULL         2.2615
2
        2.1920
2
2.2489
2
2.2762
2
2.2708
2
2.2448
2
2.2329
2
2.2804
2
2.2401
2
2.2308
2
2.1621
1
2.2810
2
2.2392
2
CCSD(T)         2.2602
3
2.2765
2
2.2805
2
2.2929
2
2.2931
2
2.2150
2
2.2688
2
2.2852
2
2.2498
5
2.2277
5
2.2448
2
2.2573
5
2.2407
3
2.2439
2
2.1801
1
2.2925
2
2.2609
2
CCSD(T)=FULL         2.2409
5
          2.2590
2
2.2866
2
2.2796
2
2.2544
2
2.2427
2
2.2909
2
2.2500
2
2.1626
1
2.1754
1
2.2916
2
2.2491
2
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 daug-cc-pVDZ daug-cc-pVTZ

average calculated bond lengths (Å)
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 2.2928
4
  2.2924
4
  2.3164
5
2.2809
5
2.2287
2
  2.2175
5
ROHF 2.2276
1
  2.2276
1
  2.2645
1
2.2275
1
2.1297
1
  2.1357
1
density functional LSDA             2.2403
2
   
BLYP             2.3060
2
  2.3053
2
B1B95 2.2812
1
          2.2418
2
  2.2414
2
B3LYP 2.3421
5
  2.3418
5
  2.3774
5
2.3402
5
2.2731
2
  2.2584
5
B3LYPultrafine             2.2731
2
  2.2729
2
B3PW91             2.2522
2
  2.2522
2
mPW1PW91             2.2452
2
  2.2455
2
M06-2X             2.2489
2
  2.2497
2
PBEPBE             2.2739
2
  2.2608
5
PBEPBEultrafine             2.2739
2
  2.2731
2
PBE1PBE             2.2438
2
  2.2442
2
HSEh1PBE             2.2482
2
  2.2484
2
TPSSh             2.2556
2
  2.2556
2
wB97X-D 2.3513
2
  2.3504
2
  2.3834
2
2.3470
2
2.2432
2
  2.2436
2
B97D3             2.2850
2
  2.2825
2
Moller Plesset perturbation MP2 2.4136
5
  2.4131
5
  2.4553
5
2.4054
5
2.2409
2
  2.2371
5
MP2=FULL             2.2378
2
  2.2393
2
ROMP2 2.3710
1
  2.3710
1
  2.4009
1
2.3623
1
2.1767
1
  2.1802
1
MP3             2.2466
2
   
MP3=FULL             2.2444
2
   
MP4             2.2560
2
   
MP4=FULL             2.2522
2
   
B2PLYP             2.2616
2
  2.2622
2
B2PLYP=FULL             2.2606
2
  2.2615
2
B2PLYP=FULLultrafine             2.2606
2
  2.2615
2
Configuration interaction CID             2.2293
2
  2.2292
2
CISD             2.2302
2
  2.2300
2
Quadratic configuration interaction QCISD             2.2456
2
  2.2472
2
QCISD(T)             2.2555
2
  2.2564
2
QCISD(T)=FULL             2.2519
2
  2.2540
2
Coupled Cluster CCD             2.2424
2
  2.2437
2
CCSD             2.2452
2
  2.2468
2
CCSD=FULL             2.2422
2
  2.2446
2
CCSD(T)             2.2549
2
  2.2561
2
CCSD(T)=FULL             2.2517
2
  2.2538
2
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.