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III.B.3.b. (XIII.C.2.)

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at B2PLYP/6-31+G**
Scale factor How many Source
Molecules Vibrations
0.952 ± 0.022 203 2898 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH3OH Methyl alcohol 1 A' 3871 3681 0.951 1 1
    2 A' 3183 3000 0.943 1 2
    3 A' 3048 2844 0.933 1 3
    4 A' 1537 1477 0.961 1 4
    5 A' 1505 1455 0.967 1 5
    6 A' 1369 1345 0.982 1 6
    7 A' 1081 1060 0.980 1 7
    8 A' 1058 1033 0.976 1 8
    9 A" 3109 2960 0.952 1 9
    10 A" 1526 1477 0.968 1 10
    11 A" 1188 1165 0.981 1 11
    12 A" 319 200 0.626 1 12
Cl2 Chlorine diatomic 1 Σg 525 560 1.066 2 13

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.

20
15
10
5
0
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