return to home page

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

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at MP2=FULL/aug-cc-pVTZ
Scale factor How many Source
Molecules Vibrations
0.967 ± 0.029 16 34 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH4 Methane 1 A1 3081 2917 0.947 1 1
    2 E 1598 1534 0.960 1 2
    3 T2 3203 3019 0.943 1 3
    4 T2 1361 1306 0.960 1 4
C2H2 Acetylene 1 Σg 3566 3374 0.946 2 5
    2 Σg 1984 1974 0.995 2 6
    3 Σu 3414 3289 0.963 2 7
    4 Πg 641 612 0.955 2 8
    5 Πu 758 730 0.964 2 9
HCN Hydrogen cyanide 1 Σ 3494 3312 0.948 3 10
    2 Σ 2048 2089 1.020 3 11
    3 Π 704 712 1.011 3 12
CO2 Carbon dioxide 1 Σg 1341 1333 0.994 4 13
    2 Σu 2422 2349 0.970 4 14
    3 Πu 668 667 0.999 4 15
CO Carbon monoxide 1 Σ 2137 2170 1.015 5 16
OH Hydroxyl radical 1 Σ 3820 3738 0.979 6 17
SO2 Sulfur dioxide 1 A1 1106 1151 1.041 7 18
    2 A1 495 518 1.046 7 19
    3 B2 1312 1362 1.038 7 20
LiH Lithium Hydride 1 Σ 1433 1405 0.981 8 21
HCl Hydrogen chloride 1 Σ 3057 2991 0.978 9 22
HF Hydrogen fluoride 1 Σ 4134 4138 1.001 10 23
NH3 Ammonia 1 A1 3535 3337 0.944 11 24
    2 A1 1026 950 0.926 11 25
    3 E 3666 3444 0.939 11 26
    4 E 1668 1627 0.975 11 27
N2 Nitrogen diatomic 1 Σg 2220 2359 1.062 12 28
H2O Water 1 A1 3849 3657 0.950 13 29
    2 A1 1623 1595 0.983 13 30
    3 B2 3971 3756 0.946 13 31
F2 Fluorine diatomic 1 Σg 1009 917 0.908 14 32
Cl2 Chlorine diatomic 1 Σg 580 560 0.965 15 33
S2 Sulfur diatomic 1 Σg 721 726 1.007 16 34

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