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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at QCISD(T)/6-31G**
Scale factor How many Source
Molecules Vibrations
0.937 ± 0.113 33 68 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
H2 Hydrogen diatomic 1 Σg 4505 4401 0.977 1 1
LiH Lithium Hydride 1 Σ 1374 1405 1.023 2 2
NaH sodium hydride 1 Σ 1137 1172 1.031 3 3
BeH beryllium monohydride 1 Σ 2093 2061 0.985 4 4
MgH magnesium monohydride 1 Σ 1467 1493 1.018 5 5
BH Boron monohydride 1 Σ 2389 2367 0.991 6 6
AlH aluminum monohydride 1 Σ 1710 1682 0.984 7 7
CH Methylidyne 1 Σ 2848 2861 1.004 8 8
SiH Silylidyne 1 Σ 2068 2043 0.988 9 9
NH Imidogen 1 Σ 3274 3283 1.003 10 10
PH phosphorus monohydride 1 Σ 2384 2364 0.992 11 11
OH Hydroxyl radical 1 Σ 3762 3738 0.993 12 12
HS Mercapto radical 1 Σ 2738 2696 0.985 13 13
CS carbon monosulfide 1 Σ 1258 1285 1.022 14 14
HF Hydrogen fluoride 1 Σ 4180 4138 0.990 15 15
HCl Hydrogen chloride 1 Σ 3056 2991 0.979 16 16
BeH2 beryllium dihydride 2 Σu 2300 2159 0.939 17 17
    3 Πu 723 698 0.966 17 18
MgH2 magnesium dihydride 2 Σu 1618 1572 0.972 18 19
    3 Πu 445 440 0.989 18 20
BH2 boron dihydride 2 A1 1079 954 0.884 19 21
AlH2 aluminum dihydride 1 A1 1870 1770 0.946 20 22
    2 A1 783 760 0.971 20 23
    3 B2 1910 1807 0.946 20 24
SiH2 silicon dihydride 1 A1 2105 1996 0.948 21 25
    2 A1 1047 999 0.954 21 26
    3 B2 2109 1993 0.945 21 27
NH2 Amino radical 1 A1 3389 3219 0.950 22 28
    2 A1 1591 1497 0.941 22 29
    3 B2 3495 3301 0.944 22 30
PH2 Phosphino radical 1 A1 2427 2310 0.952 23 31
    2 A1 1163 1102 0.948 23 32
H2O Water 1 A1 3869 3657 0.945 24 33
    2 A1 1693 1595 0.942 24 34
    3 B2 3995 3756 0.940 24 35
HO2 Hydroperoxy radical 1 A' 3688 3436 0.932 25 36
    2 A' 1426 1392 0.976 25 37
    3 A' 1101 1098 0.997 25 38
H2S Hydrogen sulfide 1 A1 2771 2615 0.944 26 39
    2 A1 1259 1183 0.940 26 40
    3 B2 2795 2626 0.940 26 41
BH3 boron trihydride 2 A2" 1193 1148 0.962 27 42
    3 E' 2773 2602 0.938 27 43
    4 E' 1256 1197 0.953 27 44
AlH3 aluminum trihydride 1 A1' 1960 1900 0.969 28 45
    2 A2" 722 698 0.966 28 46
    3 E' 1975 1883 0.953 28 47
    4 E' 808 783 0.970 28 48
SiH3 Silyl radical 1 A1 2265 2136 0.943 29 49
    2 A1 797 728 0.913 29 50
    3 E 2303 2185 0.949 29 51
    4 E 963 922 0.958 29 52
NH3 Ammonia 1 A1 3511 3337 0.950 30 53
    2 A1 1146 950 0.829 30 54
    3 E 3653 3444 0.943 30 55
    4 E 1724 1627 0.944 30 56
PH3 Phosphine 1 A1 2461 2323 0.944 31 57
    2 A1 1065 992 0.932 31 58
    3 E 2476 2328 0.940 31 59
    4 E 1156 1118 0.967 31 60
CH4 Methane 1 A1 3093 2917 0.943 32 61
    2 E 1608 1534 0.954 32 62
    3 T2 3225 3019 0.936 32 63
    4 T2 1397 1306 0.935 32 64
SiH4 Silane 1 A1 2295 2187 0.953 33 65
    2 E 996 975 0.979 33 66
    3 T2 2307 2191 0.950 33 67
    4 T2 954 914 0.958 33 68

How do we calculate the scaling factor? 2015 08 03 12:34

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