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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at ROHF/6-311G*
Scale factor How many Source
Molecules Vibrations
0.856 ± 0.159 36 57 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
MgH magnesium monohydride 1 Σ 1580 1432 0.906 1 1
CH Methylidyne 1 Σ 3065 2733 0.892 2 2
SiH Silylidyne 1 Σ 2138 1971 0.922 3 3
NH Imidogen 1 Σ 3571 3126 0.875 4 4
SiN Silicon nitride 1 Σ 1326 1138 0.859 5 5
PH phosphorus monohydride 1 Σ 2501 2276 0.910 6 6
CP Carbon monophosphide 1 Σ 1461 1226 0.839 7 7
OH Hydroxyl radical 1 Σ 4054 3570 0.881 8 8
LiO lithium oxide 1 Σ 868 799 0.920 9 9
NaO sodium monoxide 1 Σ 524     10 10
HS Mercapto radical 1 Σ 2810 2599 0.925 11 11
BS boron sulfide 1 Σ 1263 1167 0.924 12 12
AlS Aluminum sulfide 1 Σ 683 610 0.893 13 13
S2 Sulfur diatomic 1 Σg 801 720 0.899 14 14
BeF Beryllium monofluoride 1 Σ 1273     15 15
CF Fluoromethylidyne 1 Σ 1403 1286 0.916 16 16
MgF Magnesium monofluoride 1 Σ 743     17 17
SiF silicon monofluoride 1 Σ 886 848 0.957 18 18
PF phosphorus monofluoride 1 Σ 869 838 0.964 19 19
BeCl beryllium monochloride 1 Σ 844 847 1.003 20 20
CCl carbon monochloride 1 Σ 863 866 1.003 21 21
ClO Monochlorine monoxide 1 Σ 840 843 1.003 22 22
MgCl magnesium monochloride 1 Σ 456     23 23
SiCl Clorosilylidyne 1 Σ 517 531 1.028 24 24
BH2 boron dihydride 2 A1 1125 954 0.848 25 25
AlH2 aluminum dihydride 1 A1 1975 1770 0.896 26 26
    2 A1 823 760 0.924 26 27
    3 B2 1986 1807 0.910 26 28
PH2 Phosphino radical 1 A1 2529 2310 0.913 27 29
    2 A1 1254 1102 0.879 27 30
BeOH beryllium monohydroxide 2 A' 1319 1246 0.944 28 31
HCO Formyl radical 1 A' 2970 2434 0.820 29 32
    2 A' 2147 1868 0.870 29 33
    3 A' 1269 1081 0.852 29 34
HO2 Hydroperoxy radical 1 A' 4090 3436 0.840 30 35
    2 A' 1659 1392 0.839 30 36
    3 A' 1269 1098 0.865 30 37
NF2 Difluoroamino radical 1 A1 1276 1075 0.843 31 38
    2 A1 673 573 0.852 31 39
    3 B2 1189 942 0.793 31 40
ClS2 Sulfur chloride 1 A' 567 662 1.168 32 41
    2 A' 519 450 0.866 32 42
    3 A' 239 196 0.822 32 43
SiH3 Silyl radical 1 A1 2329 2136 0.917 33 44
    2 A1 897 728 0.812 33 45
    3 E 2340 2185 0.934 33 46
    4 E 1017 922 0.907 33 47
CF3 Trifluoromethyl radical 1 A1 1214 1089 0.897 34 48
    2 A1 766 701 0.915 34 49
    3 E 1421 1260 0.887 34 50
    4 E 561 509 0.906 34 51
C3H3 Propargyl radical 1 A1 3632 3322 0.915 35 52
    6 B1 737 687 0.932 35 53
    7 B1 472 490 1.038 35 54

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 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