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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=FULL/6-31+G**
Scale factor How many Source
Molecules Vibrations
0.951 ± 0.037 213 3170 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' 3184 3000 0.942 1 2
    3 A' 3049 2844 0.933 1 3
    4 A' 1538 1477 0.960 1 4
    5 A' 1506 1455 0.966 1 5
    6 A' 1369 1345 0.982 1 6
    7 A' 1082 1060 0.980 1 7
    8 A' 1059 1033 0.976 1 8
    9 A" 3110 2960 0.952 1 9
    10 A" 1527 1477 0.968 1 10
    11 A" 1188 1165 0.980 1 11
    12 A" 319 200 0.626 1 12
Cl2 Chlorine diatomic 1 Σg 525 560 1.067 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