return to home page Computational Chemistry Comparison and Benchmark DataBase Release 18 (October 2016) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Calculated > Vibrations > Scale Factors > Scale factor uncertainty

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
C2 Carbon diatomic 1 Σg 1895 1855 0.979 1 1
NH Imidogen 1 Σ 3453 3314 0.960 2 2
PH phosphorus monohydride 1 Σ 2485 2415 0.972 3 3
SO Sulfur monoxide 1 Σ 1135 1151 1.014 4 4
    1 Σ 1020 1069 1.047 4 5
C3H2N2 Malononitrile 1 A1 3130 2935 0.938 5 6
    2 A1 2243 2275 1.014 5 7
    3 A1 1475 1395 0.945 5 8
    4 A1 918 890 0.970 5 9
    5 A1 590 582 0.986 5 10
    6 A1 152 167 1.098 5 11
    7 A2 1286 1220 0.948 5 12
    8 A2 399 367 0.919 5 13
    9 B1 3186 2968 0.931 5 14
    10 B1 955 933 0.977 5 15
    11 B1 367 337 0.918 5 16
    12 B2 2248 2275 1.012 5 17
    13 B2 1362 1318 0.968 5 18
    14 B2 1010 982 0.972 5 19
    15 B2 392 366 0.934 5 20

How do we calculate the scaling factor? 2015 08 03 12:34

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