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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at ROHF/3-21G
Scale factor How many Source
Molecules Vibrations
0.907 ± 0.178 35 56 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
MgH magnesium monohydride 1 Σ 1587 1432 0.902 1 1
CH Methylidyne 1 Σ 2886 2733 0.947 2 2
SiH Silylidyne 1 Σ 2032 1971 0.970 3 3
NH Imidogen 1 Σ 3233 3126 0.967 4 4
SiN Silicon nitride 1 Σ 1245 1138 0.914 5 5
PH phosphorus monohydride 1 Σ 2301 2276 0.989 6 6
CP Carbon monophosphide 1 Σ 1335 1226 0.918 7 7
OH Hydroxyl radical 1 Σ 3633 3570 0.983 8 8
LiO lithium oxide 1 Σ 929 799 0.860 9 9
NaO sodium monoxide 1 Σ 536     10 10
HS Mercapto radical 1 Σ 2596 2599 1.001 11 11
BS boron sulfide 1 Σ 1199 1167 0.974 12 12
SO Sulfur monoxide 1 Σ 1136 1138 1.001 13 13
AlS Aluminum sulfide 1 Σ 571 610 1.069 14 14
S2 Sulfur diatomic 1 Σg 635 720 1.133 15 15
BeF Beryllium monofluoride 1 Σ 1402     16 16
CF Fluoromethylidyne 1 Σ 1331 1286 0.966 17 17
MgF Magnesium monofluoride 1 Σ 798     18 18
SiF silicon monofluoride 1 Σ 928 848 0.913 19 19
BeCl beryllium monochloride 1 Σ 801 847 1.057 20 20
CCl carbon monochloride 1 Σ 630 866 1.374 21 21
ClO Monochlorine monoxide 1 Σ 796 843 1.058 22 22
MgCl magnesium monochloride 1 Σ 441     23 23
SiCl Clorosilylidyne 1 Σ 432 531 1.229 24 24
BH2 boron dihydride 2 A1 1112 954 0.858 25 25
AlH2 aluminum dihydride 1 A1 1922 1770 0.921 26 26
    2 A1 781 760 0.973 26 27
    3 B2 1938 1807 0.932 26 28
PH2 Phosphino radical 1 A1 2350 2310 0.983 27 29
    2 A1 1222 1102 0.902 27 30
HCO Formyl radical 1 A' 3026 2434 0.805 28 31
    2 A' 2030 1868 0.920 28 32
    3 A' 1249 1081 0.865 28 33
HO2 Hydroperoxy radical 1 A' 3780 3436 0.909 29 34
    2 A' 1496 1392 0.930 29 35
    3 A' 1136 1098 0.966 29 36
NF2 Difluoroamino radical 1 A1 1119 1075 0.961 30 37
    2 A1 543 573 1.055 30 38
    3 B2 1094 942 0.861 30 39
OClO Chlorine dioxide 1 A1 655 946 1.443 31 40
    2 A1 295 448 1.516 31 41
    3 B2 909 1110 1.221 31 42
ClS2 Sulfur chloride 1 A' 469 662 1.413 32 43
    2 A' 431 450 1.044 32 44
    3 A' 180 196 1.090 32 45
SiH3 Silyl radical 1 A1 2269 2136 0.942 33 46
    2 A1 819 728 0.889 33 47
    3 E 2288 2185 0.955 33 48
    4 E 992 922 0.929 33 49
CF3 Trifluoromethyl radical 1 A1 1160 1089 0.939 34 50
    2 A1 709 701 0.989 34 51
    3 E 1451 1260 0.868 34 52
    4 E 520 509 0.978 34 53

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 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