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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at CCSD(T)/cc-pVTZ
Scale factor How many Source
Molecules Vibrations
0.975 ± 0.021 30 61 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
H2 Hydrogen diatomic 1 Σg 4411 4161 0.943 1 1
BH Boron monohydride 1 Σ 2351 2269 0.965 2 2
AlH aluminum monohydride 1 Σ 1681 1625 0.967 3 3
CH Methylidyne 1 Σ 2835 2733 0.964 4 4
    1 Σ 3109     4 5
C2 Carbon diatomic 1 Σg 1846 1827 0.990 5 6
SiH Silylidyne 1 Σ 2031 1971 0.971 6 7
Si2 Silicon diatomic 1 Σg 543 507 0.934 7 8
NH Imidogen 1 Σ 3266 3126 0.957 8 9
PH phosphorus monohydride 1 Σ 2352 2276 0.968 9 10
    1 Σ 2373 2319 0.977 9 11
OH Hydroxyl radical 1 Σ 3740 3570 0.954 10 12
HS Mercapto radical 1 Σ 2687 2599 0.967 11 13
CS carbon monosulfide 1 Σ 1269 1272 1.002 12 14
HF Hydrogen fluoride 1 Σ 4181 3961 0.947 13 15
F2 Fluorine diatomic 1 Σg 920 894 0.972 14 16
HCl Hydrogen chloride 1 Σ 3001 2886 0.962 15 17
CCl carbon monochloride 1 Σ 866 866 1.000 16 18
BH2 boron dihydride 2 A1 1018 954 0.937 17 19
AlH2 aluminum dihydride 1 A1 1847 1770 0.958 18 20
    2 A1 766 760 0.993 18 21
    3 B2 1883 1807 0.959 18 22
SiH2 silicon dihydride 1 A1 2064 1996 0.967 19 23
    2 A1 1023 999 0.977 19 24
    3 B2 2063 1993 0.966 19 25
PH2 Phosphino radical 1 A1 2386 2310 0.968 20 26
    2 A1 1125 1102 0.980 20 27
H2O Water 1 A1 3840 3657 0.952 21 28
    2 A1 1668 1595 0.956 21 29
    3 B2 3945 3756 0.952 21 30
H2S Hydrogen sulfide 1 A1 2717 2615 0.962 22 31
    2 A1 1204 1183 0.982 22 32
    3 B2 2733 2626 0.961 22 33
BH3 boron trihydride 2 A2" 1160 1148 0.989 23 34
    3 E' 2698 2602 0.964 23 35
    4 E' 1223 1197 0.979 23 36
AlH3 aluminum trihydride 1 A1' 1940 1900 0.979 24 37
    2 A2" 718 698 0.972 24 38
    3 E' 1947 1883 0.967 24 39
    4 E' 792 783 0.989 24 40
SiH3 Silyl radical 1 A1 2218 2136 0.963 25 41
    2 A1 774 728 0.940 25 42
    3 E 2253 2185 0.970 25 43
    4 E 940 922 0.981 25 44
NH3 Ammonia 1 A1 3471 3337 0.961 26 45
    2 A1 1112 950 0.854 26 46
    3 E 3596 3444 0.958 26 47
    4 E 1688 1627 0.964 26 48
PH3 Phosphine 1 A1 2412 2323 0.963 27 49
    2 A1 1018 992 0.974 27 50
    3 E 2421 2328 0.962 27 51
    4 E 1142 1118 0.979 27 52
CH4 Methane 1 A1 3036 2917 0.961 28 53
    2 E 1570 1534 0.977 28 54
    3 T2 3155 3019 0.957 28 55
    4 T2 1343 1306 0.972 28 56
SiH4 Silane 1 A1 2251 2187 0.971 29 57
    2 E 987 975 0.988 29 58
    3 T2 2259 2191 0.970 29 59
    4 T2 933 914 0.980 29 60

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 45 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 35 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 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