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

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at MP2=FULL/6-31G(2df,p)
Scale factor How many Source
Molecules Vibrations
0.942 ± 0.036 11 69 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
SO Sulfur monoxide 1 Σ 1020 1069 1.047 1 1
    1 Σ 1135 1151 1.014 1 2
NH Imidogen 1 Σ 3453 3314 0.960 2 3
C3H2N2 Malononitrile 15 B2 392 366 0.934 3 4
    14 B2 1010 982 0.972 3 5
    13 B2 1362 1318 0.968 3 6
    12 B2 2248 2275 1.012 3 7
    11 B1 367 337 0.918 3 8
    10 B1 955 933 0.977 3 9
    9 B1 3186 2968 0.931 3 10
    8 A2 399 367 0.919 3 11
    7 A2 1286 1220 0.948 3 12
    6 A1 152 167 1.098 3 13
    5 A1 590 582 0.986 3 14
    4 A1 918 890 0.970 3 15
    3 A1 1475 1395 0.945 3 16
    2 A1 2243 2275 1.014 3 17
    1 A1 3130 2935 0.938 3 18
PH phosphorus monohydride 1 Σ 2485 2415 0.972 4 19

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