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III.B.3.b. (XIII.C.2.)

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
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH4 Methane 1 A1 3080 2917 0.947 1 1
    2 E 1596 1534 0.961 1 2
    3 T2 3197 3019 0.944 1 3
    4 T2 1371 1306 0.953 1 4
H2 Hydrogen diatomic 1 Σg 4411 4401 0.998 2 5
CS carbon monosulfide 1 Σ 1359 1285 0.946 3 6
HO2 Hydroperoxy radical 1 A' 3841 3436 0.895 4 7
    2 A' 1511 1392 0.921 4 8
    3 A' 1231 1098 0.892 4 9
CH Methylidyne 1 Σ 2873 2861 0.996 5 10
OH Hydroxyl radical 1 Σ 3820 3738 0.978 6 11
HCl Hydrogen chloride 1 Σ 3053 2991 0.980 7 12
HF Hydrogen fluoride 1 Σ 4258 4138 0.972 8 13
NH3 Ammonia 1 A1 3550 3337 0.940 9 14
    2 A1 1110 950 0.856 9 15
    3 E 3673 3444 0.938 9 16
    4 E 1715 1627 0.949 9 17
H2O Water 1 A1 3934 3657 0.930 10 18
    2 A1 1690 1595 0.944 10 19
    3 B2 4033 3756 0.931 10 20
H2S Hydrogen sulfide 1 A1 2770 2615 0.944 11 21
    2 A1 1236 1183 0.957 11 22
    3 B2 2783 2626 0.944 11 23
AlH3 aluminum trihydride 1 A1' 1960 1900 0.969 12 24
    2 A2" 726 698 0.961 12 25
    3 E' 1964 1883 0.959 12 26
    4 E' 801 783 0.978 12 27
PH3 Phosphine 1 A1 2463 2323 0.943 13 28
    2 A1 1041 992 0.953 13 29
    3 E 2469 2328 0.943 13 30
    4 E 1169 1118 0.956 13 31
SiH4 Silane 1 A1 2282 2187 0.958 14 32
    2 E 1000 975 0.975 14 33
    3 T2 2286 2191 0.958 14 34
    4 T2 951 914 0.961 14 35
BH3 boron trihydride 2 A2" 1172 1148 0.979 15 36
    3 E' 2719 2602 0.957 15 37
    4 E' 1236 1197 0.968 15 38
PH2 Phosphino radical 1 A1 2427 2310 0.952 16 39
    2 A1 1149 1102 0.959 16 40
SiH3 Silyl radical 1 A1 2245 2136 0.951 17 41
    2 A1 798 728 0.913 17 42
    3 E 2278 2185 0.959 17 43
    4 E 956 922 0.964 17 44
BH Boron monohydride 1 Σ 2373 2367 0.998 18 45
NH2 Amino radical 1 A1 3436 3219 0.937 19 46
    2 A1 1578 1497 0.949 19 47
    3 B2 3525 3301 0.937 19 48
NH Imidogen 1 Σ 3323 3283 0.988 20 49
SiH Silylidyne 1 Σ 2054 2043 0.994 21 50
SiH2 silicon dihydride 1 A1 2095 1996 0.953 22 51
    2 A1 1044 999 0.957 22 52
    3 B2 2091 1993 0.953 22 53
SH Mercapto radical 1 Σ 2734 2696 0.986 23 54
PH phosphorus monohydride 1 Σ 2387 2364 0.990 24 55
AlH aluminum monohydride 1 Σ 1692 1682 0.994 25 56
BH2 boron dihydride 2 A1 1028 954 0.928 26 57
AlH2 aluminum dihydride 1 A1 1864 1770 0.950 27 58
    2 A1 774 760 0.981 27 59
    3 B2 1897 1807 0.952 27 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.

45
40
35
30
25
20
15
10
5
0
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