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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at CCSD(T)=FULL/6-31G*
Scale factor How many Source
Molecules Vibrations
0.971 ± 0.031 30 95 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
LiH Lithium Hydride 1 Σ 1332 1405 1.055 1 1
CH Methylidyne 1 Σ 3174 3145 0.991 2 2
CN Cyano radical 1 Σ 2120 2069 0.976 3 3
N2 Nitrogen diatomic 1 Σg 2345 2359 1.006 4 4
OH Hydroxyl radical 1 Σ 3630 3738 1.030 5 5
CO Carbon monoxide 1 Σ 2159 2170 1.005 6 6
MgO magnesium oxide 1 Σ 747 785 1.051 7 7
HF Hydrogen fluoride 1 Σ 4006 4138 1.033 8 8
F2 Fluorine diatomic 1 Σg 890 917 1.031 9 9
HCl Hydrogen chloride 1 Σ 2962 2991 1.010 10 10
Cl2 Chlorine diatomic 1 Σg 503 560 1.112 11 11
MgH2 magnesium dihydride 2 Σu 1583 1572 0.993 12 12
    3 Πu 442 440 0.996 12 13
HCN Hydrogen cyanide 1 Σ 3466 3312 0.955 13 14
    2 Σ 2130 2089 0.981 13 15
    3 Π 714 712 0.998 13 16
H2O Water 1 A1 3726 3657 0.981 14 17
    2 A1 1742 1595 0.916 14 18
    3 B2 3856 3756 0.974 14 19
CO2 Carbon dioxide 1 Σg 1349 1333 0.989 15 20
    2 Σu 2417 2349 0.972 15 21
    3 Πu 645 667 1.035 15 22
H2S Hydrogen sulfide 1 A1 2702 2615 0.968 16 23
    2 A1 1257 1183 0.941 16 24
    3 B2 2726 2626 0.963 16 25
SO2 Sulfur dioxide 1 A1 1111 1151 1.036 17 26
    2 A1 499 518 1.038 17 27
    3 B2 1324 1362 1.028 17 28
CS2 Carbon disulfide 1 Σg 673 658 0.977 18 29
    2 Σu 1571 1535 0.977 18 30
    3 Πu 397 397 1.000 18 31
ClCN chlorocyanogen 1 Σ 2264 2216 0.979 19 32
    2 Σ 741 744 1.004 19 33
    3 Π 355 378 1.065 19 34
AlH3 aluminum trihydride 1 A1' 1924 1900 0.988 20 35
    2 A2" 702 698 0.994 20 36
    3 E' 1942 1883 0.970 20 37
    4 E' 786 783 0.997 20 38
C2H2 Acetylene 1 Σg 3520 3374 0.959 21 39
    2 Σg 2024 1974 0.976 21 40
    3 Σu 3425 3289 0.960 21 41
    4 Πg 358 612 1.708 21 42
    5 Πu 735 730 0.993 21 43
NH3 Ammonia 1 A1 3435 3337 0.972 22 44
    2 A1 1180 950 0.805 22 45
    3 E 3576 3444 0.963 22 46
    4 E 1747 1627 0.932 22 47
H2CO Formaldehyde 1 A1 2956 2782 0.941 23 48
    2 A1 1795 1746 0.973 23 49
    3 A1 1566 1500 0.958 23 50
    4 B1 1185 1167 0.985 23 51
    5 B2 3021 2843 0.941 23 52
    6 B2 1285 1249 0.972 23 53
H2O2 Hydrogen peroxide 1 A 3698 3599 0.973 24 54
    2 A 1455 1402 0.964 24 55
    3 A 879 877 0.998 24 56
    4 A 326 371 1.137 24 57
    5 B 3701 3608 0.975 24 58
    6 B 1311 1266 0.965 24 59
H2CS Thioformaldehyde 1 A1 3111 2971 0.955 25 60
    2 A1 1544 1456 0.943 25 61
    3 A1 1071 1059 0.989 25 62
    4 B1 1009 990 0.981 25 63
    5 B2 3200 3025 0.945 25 64
    6 B2 1036 991 0.957 25 65
BF3 Borane, trifluoro- 1 A1' 892 888 0.995 26 66
    2 A2" 701 691 0.985 26 67
    3 E' 1505 1449 0.963 26 68
    4 E' 483 480 0.994 26 69
CH4 Methane 1 A1 3246 2917 0.899 27 70
    2 E 1756 1534 0.874 27 71
    3 T2 3480 3019 0.868 27 72
    4 T2 1537 1306 0.850 27 73
HCOOH Formic acid 1 A' 3661 3570 0.975 28 74
    2 A' 3113 2943 0.945 28 75
    3 A' 1846 1770 0.959 28 76
    4 A' 1432 1387 0.968 28 77
    5 A' 1344 1229 0.915 28 78
    6 A' 1153 1105 0.958 28 79
    7 A' 626 625 0.998 28 80
    8 A" 1054 1033 0.980 28 81
    9 A" 701 638 0.911 28 82
C2H6 Ethane 1 A1g 3055 2954 0.967 29 83
    2 A1g 1476 1388 0.940 29 84
    3 A1g 1034 995 0.962 29 85
    4 A1u 322 289 0.898 29 86
    5 A2u 3054 2896 0.948 29 87
    6 A2u 1449 1379 0.952 29 88
    7 Eg 3116 2969 0.953 29 89
    8 Eg 1546 1468 0.950 29 90
    9 Eg 1256 1190 0.948 29 91
    10 Eu 3138 2985 0.951 29 92
    11 Eu 1551 1469 0.947 29 93
    12 Eu 839 822 0.980 29 94

How do we calculate the scaling factor? 2015 08 03 12:34

Histogram of vibrational frequency ratios

Ratios greater than 1.35 are in the 1.35 bin. Ratios less than 0.7 are in the 0.7 bin.

40 40 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 35 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 30 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 25 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 20 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 15 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 10 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35
Ratio of experimental frequency to calculated frequency