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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at CISD/cc-pVTZ
Scale factor How many Source
Molecules Vibrations
0.930 ± 0.122 27 60 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 2373 2269 0.956 2 2
AlH aluminum monohydride 1 Σ 1692 1625 0.961 3 3
CH Methylidyne 1 Σ 2873 2733 0.951 4 4
SiH Silylidyne 1 Σ 2054 1971 0.959 5 5
NH Imidogen 1 Σ 3323 3126 0.941 6 6
PH phosphorus monohydride 1 Σ 2387 2276 0.954 7 7
OH Hydroxyl radical 1 Σ 3820 3570 0.934 8 8
HS Mercapto radical 1 Σ 2734 2599 0.951 9 9
CS carbon monosulfide 1 Σ 1359 1272 0.936 10 10
HF Hydrogen fluoride 1 Σ 4258 3961 0.930 11 11
HCl Hydrogen chloride 1 Σ 3053 2886 0.945 12 12
BH2 boron dihydride 2 A1 1028 954 0.928 13 13
AlH2 aluminum dihydride 1 A1 1864 1770 0.950 14 14
    2 A1 774 760 0.981 14 15
    3 B2 1897 1807 0.952 14 16
SiH2 silicon dihydride 1 A1 2095 1996 0.953 15 17
    2 A1 1044 999 0.957 15 18
    3 B2 2091 1993 0.953 15 19
PH2 Phosphino radical 1 A1 2427 2310 0.952 16 20
    2 A1 1149 1102 0.959 16 21
H2O Water 1 A1 3932 3657 0.930 17 22
    2 A1 1690 1595 0.944 17 23
    3 B2 4032 3756 0.932 17 24
HO2 Hydroperoxy radical 1 A' 3841 3436 0.895 18 25
    2 A' 1511 1392 0.921 18 26
    3 A' 1231 1098 0.892 18 27
H2S Hydrogen sulfide 1 A1 2770 2615 0.944 19 28
    2 A1 1236 1183 0.957 19 29
    3 B2 2783 2626 0.944 19 30
BH3 boron trihydride 2 A2" 1172 1148 0.979 20 31
    3 E' 2719 2602 0.957 20 32
    4 E' 1236 1197 0.968 20 33
AlH3 aluminum trihydride 1 A1' 1960 1900 0.969 21 34
    2 A2" 726 698 0.961 21 35
    3 E' 1964 1883 0.959 21 36
    4 E' 801 783 0.978 21 37
SiH3 Silyl radical 1 A1 2245 2136 0.951 22 38
    2 A1 798 728 0.913 22 39
    3 E 2278 2185 0.959 22 40
    4 E 956 922 0.964 22 41
NH3 Ammonia 1 A1 3550 3337 0.940 23 42
    2 A1 1110 950 0.856 23 43
    3 E 3673 3444 0.938 23 44
    4 E 1715 1627 0.949 23 45
PH3 Phosphine 1 A1 2463 2323 0.943 24 46
    2 A1 1041 992 0.953 24 47
    3 E 2469 2328 0.943 24 48
    4 E 1169 1118 0.956 24 49
CH4 Methane 1 A1 3080 2917 0.947 25 50
    2 E 1596 1534 0.961 25 51
    3 T2 3197 3019 0.944 25 52
    4 T2 1371 1306 0.953 25 53
SiH4 Silane 1 A1 2282 2187 0.958 26 54
    2 E 1000 975 0.975 26 55
    3 T2 2286 2191 0.958 26 56
    4 T2 951 914 0.961 26 57

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 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