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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
CF Fluoromethylidyne 1 Σ 1310 1308 0.999 9 9
F2 Fluorine diatomic 1 Σg 890 917 1.031 10 10
HCl Hydrogen chloride 1 Σ 2962 2991 1.010 11 11
Cl2 Chlorine diatomic 1 Σg 503 560 1.112 12 12
MgH2 magnesium dihydride 2 Σu 1583 1572 0.993 13 13
    3 Πu 442 440 0.996 13 14
HCN Hydrogen cyanide 1 Σ 3466 3312 0.955 14 15
    2 Σ 2130 2089 0.981 14 16
    3 Π 714 712 0.998 14 17
H2O Water 1 A1 3726 3657 0.981 15 18
    2 A1 1742 1595 0.916 15 19
    3 B2 3856 3756 0.974 15 20
CO2 Carbon dioxide 1 Σg 1349 1333 0.989 16 21
    2 Σu 2417 2349 0.972 16 22
    3 Πu 645 667 1.035 16 23
H2S Hydrogen sulfide 1 A1 2702 2615 0.968 17 24
    2 A1 1257 1183 0.941 17 25
    3 B2 2726 2626 0.963 17 26
SO2 Sulfur dioxide 1 A1 1111 1151 1.036 18 27
    2 A1 499 518 1.038 18 28
    3 B2 1324 1362 1.028 18 29
CS2 Carbon disulfide 1 Σg 673 658 0.977 19 30
    2 Σu 1571 1535 0.977 19 31
    3 Πu 397 397 1.000 19 32
ClCN chlorocyanogen 1 Σ 2264 2216 0.979 20 33
    2 Σ 741 744 1.004 20 34
    3 Π 355 378 1.065 20 35
AlH3 aluminum trihydride 1 A1' 1924 1900 0.988 21 36
    2 A2" 702 698 0.994 21 37
    3 E' 1942 1883 0.970 21 38
    4 E' 786 783 0.997 21 39
C2H2 Acetylene 1 Σg 3520 3374 0.959 22 40
    2 Σg 2024 1974 0.976 22 41
    3 Σu 3425 3289 0.960 22 42
    4 Πg 358 612 1.708 22 43
    5 Πu 735 730 0.993 22 44
NH3 Ammonia 1 A1 3435 3337 0.972 23 45
    2 A1 1180 950 0.805 23 46
    3 E 3576 3444 0.963 23 47
    4 E 1747 1627 0.932 23 48
H2CO Formaldehyde 1 A1 2956 2782 0.941 24 49
    2 A1 1795 1746 0.973 24 50
    3 A1 1566 1500 0.958 24 51
    4 B1 1185 1167 0.985 24 52
    5 B2 3021 2843 0.941 24 53
    6 B2 1285 1249 0.972 24 54
H2O2 Hydrogen peroxide 1 A 3698 3599 0.973 25 55
    2 A 1455 1402 0.964 25 56
    3 A 879 877 0.998 25 57
    4 A 326 371 1.137 25 58
    5 B 3701 3608 0.975 25 59
    6 B 1311 1266 0.965 25 60
H2CS Thioformaldehyde 1 A1 3111 2971 0.955 26 61
    2 A1 1544 1456 0.943 26 62
    3 A1 1071 1059 0.989 26 63
    4 B1 1009 990 0.981 26 64
    5 B2 3200 3025 0.945 26 65
    6 B2 1036 991 0.957 26 66
BF3 Borane, trifluoro- 1 A1' 892 888 0.995 27 67
    2 A2" 701 691 0.985 27 68
    3 E' 1505 1449 0.963 27 69
    4 E' 483 480 0.994 27 70
CH4 Methane 1 A1 3246 2917 0.899 28 71
    2 E 1756 1534 0.874 28 72
    3 T2 3480 3019 0.868 28 73
    4 T2 1537 1306 0.850 28 74
HCOOH Formic acid 1 A' 3661 3570 0.975 29 75
    2 A' 3113 2943 0.945 29 76
    3 A' 1846 1770 0.959 29 77
    4 A' 1432 1387 0.968 29 78
    5 A' 1344 1229 0.915 29 79
    6 A' 1153 1105 0.958 29 80
    7 A' 626 625 0.998 29 81
    8 A" 1054 1033 0.980 29 82
    9 A" 701 638 0.911 29 83
C2H6 Ethane 1 A1g 3055 2954 0.967 30 84
    2 A1g 1476 1388 0.940 30 85
    3 A1g 1034 995 0.962 30 86
    4 A1u 322 289 0.899 30 87
    5 A2u 3054 2896 0.948 30 88
    6 A2u 1449 1379 0.952 30 89
    7 Eg 3116 2969 0.953 30 90
    8 Eg 1546 1468 0.950 30 91
    9 Eg 1256 1190 0.948 30 92
    10 Eu 3138 2985 0.951 30 93
    11 Eu 1551 1469 0.947 30 94
    12 Eu 839 822 0.980 30 95

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