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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at ROHF/6-311G**
Scale factor How many Source
Molecules Vibrations
0.913 ± 0.048 12 37 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
BeH beryllium monohydride 1 Σ 2135 1987 0.930 1 1
BN boron nitride 1 Σ 1792 1490 0.831 2 2
AlN Aluminum nitride 1 Σ 730 747 1.023 3 3
BO boron monoxide 1 Σ 2108 1862 0.883 4 4
NO Nitric oxide 1 Σ 2279 1876 0.823 5 5
HSe Selenium monohydride 1 Σ 2563     6 6
SeO Selenium monoxide 1 Σ 1074 906 0.843 7 7
C2H3 vinyl 1 A' 3378 3141 0.930 8 8
    2 A' 3336 2953 0.885 8 9
    3 A' 3250 2912 0.896 8 10
    5 A' 1505 1360 0.903 8 11
    7 A' 826 674 0.816 8 12
    8 A" 1052 895 0.851 8 13
    9 A" 964 857 0.889 8 14
CH2OH Hydroxymethyl radical 1 A 4189 3650 0.871 9 15
    4 A 1609 1459 0.907 9 16
    5 A 1473 1334 0.906 9 17
    6 A 1276 1176 0.922 9 18
    7 A 1154 1048 0.908 9 19
    8 A 901 482 0.535 9 20
    9 A 416 234 0.563 9 21
C2H5 Ethyl radical 1 A' 3271 3033 0.927 10 22
    2 A' 3191 2842 0.891 10 23
    5 A' 1587 1440 0.907 10 24
    6 A' 1524 1366 0.896 10 25
    7 A' 1107 1138 1.028 10 26
    9 A' 530 528 0.997 10 27
    10 A" 3369 3112 0.924 10 28
    11 A" 3223 2987 0.927 10 29
    12 A" 1605 1440 0.897 10 30
    13 A" 1299 1175 0.904 10 31

How do we calculate the scaling factor?

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 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