return to home page Computational Chemistry Comparison and Benchmark DataBase Release 21 (August 2020) 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 CCSD/6-31+G**
Scale factor How many Source
Molecules Vibrations
0.934 ± 0.113 32 67 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
H2 Hydrogen diatomic 1 Σg 4504 4161 0.924 1 1
LiH Lithium Hydride 1 Σ 1375 1360 0.989 2 2
NaH sodium hydride 1 Σ 1138 1133 0.996 3 3
BeH beryllium monohydride 1 Σ 2098 1987 0.947 4 4
MgH magnesium monohydride 1 Σ 1473 1432 0.972 5 5
BH Boron monohydride 1 Σ 2415 2269 0.940 6 6
AlH aluminum monohydride 1 Σ 1719 1625 0.946 7 7
CH Methylidyne 1 Σ 2889 2733 0.946 8 8
SiH Silylidyne 1 Σ 2081 1971 0.947 9 9
NH Imidogen 1 Σ 3311 3126 0.944 10 10
PH phosphorus monohydride 1 Σ 2398 2276 0.949 11 11
OH Hydroxyl radical 1 Σ 3769 3570 0.947 12 12
HS Mercapto radical 1 Σ 2744 2599 0.947 13 13
CS carbon monosulfide 1 Σ 1335 1272 0.953 14 14
HF Hydrogen fluoride 1 Σ 4150 3961 0.955 15 15
HCl Hydrogen chloride 1 Σ 3064 2886 0.942 16 16
BeH2 beryllium dihydride 2 Σu 2293 2159 0.942 17 17
    3 Πu 717 698 0.973 17 18
MgH2 magnesium dihydride 2 Σu 1619 1572 0.971 18 19
    3 Πu 447 440 0.984 18 20
AlH2 aluminum dihydride 1 A1 1882 1770 0.940 19 21
    2 A1 790 760 0.962 19 22
    3 B2 1921 1807 0.940 19 23
SiH2 silicon dihydride 1 A1 2116 1996 0.943 20 24
    2 A1 1054 999 0.948 20 25
    3 B2 2118 1993 0.941 20 26
PH2 Phosphino radical 1 A1 2439 2310 0.947 21 27
    2 A1 1169 1102 0.943 21 28
H2O Water 1 A1 3880 3657 0.943 22 29
    2 A1 1647 1595 0.968 22 30
    3 B2 4009 3756 0.937 22 31
HO2 Hydroperoxy radical 1 A' 3713 3436 0.925 23 32
    2 A' 1447 1392 0.962 23 33
    3 A' 1130 1098 0.971 23 34
H2S Hydrogen sulfide 1 A1 2782 2615 0.940 24 35
    2 A1 1265 1183 0.935 24 36
    3 B2 2804 2626 0.936 24 37
BH3 boron trihydride 2 A2" 1192 1148 0.963 25 38
    3 E' 2769 2602 0.940 25 39
    4 E' 1253 1197 0.955 25 40
AlH3 aluminum trihydride 1 A1' 1972 1900 0.963 26 41
    2 A2" 726 698 0.961 26 42
    3 E' 1985 1883 0.949 26 43
    4 E' 814 783 0.962 26 44
SiH3 Silyl radical 1 A1 2278 2136 0.938 27 45
    2 A1 804 728 0.905 27 46
    3 E 2313 2185 0.945 27 47
    4 E 969 922 0.952 27 48
NH3 Ammonia 1 A1 3549 3337 0.940 28 49
    2 A1 1072 950 0.886 28 50
    3 E 3700 3444 0.931 28 51
    4 E 1713 1627 0.950 28 52
PH3 Phosphine 1 A1 2470 2323 0.941 29 53
    2 A1 1068 992 0.929 29 54
    3 E 2483 2328 0.938 29 55
    4 E 1163 1118 0.961 29 56
CH4 Methane 1 A1 3097 2917 0.942 30 57
    2 E 1593 1534 0.963 30 58
    3 T2 3225 3019 0.936 30 59
    4 T2 1396 1306 0.936 30 60
SiH4 Silane 1 A1 2308 2187 0.948 31 61
    2 E 1002 975 0.973 31 62
    3 T2 2317 2191 0.946 31 63
    4 T2 961 914 0.951 31 64

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 60 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 50 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 40 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 30 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 10 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