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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/3-21G
Scale factor How many Source
Molecules Vibrations
0.952 ± 0.047 214 3176 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH3OH Methyl alcohol 1 A' 3499 3681 1.052 1 1
    2 A' 3161 3000 0.949 1 2
    3 A' 3027 2844 0.940 1 3
    4 A' 1606 1477 0.920 1 4
    5 A' 1543 1455 0.943 1 5
    6 A' 1410 1345 0.954 1 6
    7 A' 1092 1060 0.971 1 7
    8 A' 993 1033 1.041 1 8
    9 A" 3064 2960 0.966 1 9
    10 A" 1588 1477 0.930 1 10
    11 A" 1168 1165 0.998 1 11
    12 A" 385 200 0.519 1 12
Cl2 Chlorine diatomic 1 Σg 458 560 1.221 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