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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at ROHF/6-31+G**
Scale factor How many Source
Molecules Vibrations
0.856 ± 0.155 39 62 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
MgH magnesium monohydride 1 Σ 1575 1432 0.909 1 1
CH Methylidyne 1 Σ 3061 2733 0.893 2 2
SiH Silylidyne 1 Σ 2162 1971 0.912 3 3
NH Imidogen 1 Σ 3565 3126 0.877 4 4
SiN Silicon nitride 1 Σ 1306 1138 0.871 5 5
PH phosphorus monohydride 1 Σ 2551 2276 0.892 6 6
CP Carbon monophosphide 1 Σ 1447 1226 0.847 7 7
OH Hydroxyl radical 1 Σ 4072 3570 0.877 8 8
LiO lithium oxide 1 Σ 844 799 0.947 9 9
NaO sodium monoxide 1 Σ 499     10 10
HS Mercapto radical 1 Σ 2878 2599 0.903 11 11
BS boron sulfide 1 Σ 1266 1167 0.922 12 12
SO Sulfur monoxide 1 Σ 1340 1138 0.849 13 13
AlS Aluminum sulfide 1 Σ 679 610 0.898 14 14
S2 Sulfur diatomic 1 Σg 816 720 0.883 15 15
BeF Beryllium monofluoride 1 Σ 1270     16 16
CF Fluoromethylidyne 1 Σ 1380 1286 0.932 17 17
NF nitrogen fluoride 1 Σ 1237 1123 0.908 18 18
MgF Magnesium monofluoride 1 Σ 728     19 19
SiF silicon monofluoride 1 Σ 873 848 0.971 20 20
PF phosphorus monofluoride 1 Σ 875 838 0.958 21 21
BeCl beryllium monochloride 1 Σ 856 847 0.990 22 22
CCl carbon monochloride 1 Σ 876 866 0.988 23 23
ClO Monochlorine monoxide 1 Σ 863 843 0.977 24 24
MgCl magnesium monochloride 1 Σ 455     25 25
SiCl Clorosilylidyne 1 Σ 526 531 1.011 26 26
BH2 boron dihydride 2 A1 1127 954 0.846 27 27
AlH2 aluminum dihydride 1 A1 1962 1770 0.902 28 28
    2 A1 825 760 0.921 28 29
    3 B2 1975 1807 0.915 28 30
PH2 Phosphino radical 1 A1 2553 2310 0.905 29 31
    2 A1 1241 1102 0.888 29 32
HCO Formyl radical 1 A' 3005 2434 0.810 30 33
    2 A' 2138 1868 0.874 30 34
    3 A' 1253 1081 0.863 30 35
HO2 Hydroperoxy radical 1 A' 4087 3436 0.841 31 36
    2 A' 1601 1392 0.869 31 37
    3 A' 1251 1098 0.877 31 38
NF2 Difluoroamino radical 1 A1 1252 1075 0.859 32 39
    2 A1 653 573 0.878 32 40
    3 B2 1168 942 0.807 32 41
OClO Chlorine dioxide 1 A1 1060 946 0.892 33 42
    2 A1 509 448 0.880 33 43
    3 B2 1257 1110 0.883 33 44
ClS2 Sulfur chloride 1 A' 593 662 1.116 34 45
    2 A' 525 450 0.857 34 46
    3 A' 239 196 0.819 34 47
SiH3 Silyl radical 1 A1 2364 2136 0.904 35 48
    2 A1 901 728 0.808 35 49
    3 E 2383 2185 0.917 35 50
    4 E 1018 922 0.906 35 51
CF3 Trifluoromethyl radical 1 A1 1206 1089 0.903 36 52
    2 A1 756 701 0.927 36 53
    3 E 1416 1260 0.890 36 54
    4 E 550 509 0.925 36 55
C3H3 Propargyl radical 1 A1 3638 3322 0.913 37 56
    6 B1 765 687 0.898 37 57
    7 B1 519 490 0.945 37 58

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.

40 30 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 25 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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