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

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at QCISD(T)/cc-pVTZ
Scale factor How many Source
Molecules Vibrations
0.949 ± 0.118 27 60 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH4 Methane 1 A1 3035 2917 0.961 1 1
    2 E 1570 1534 0.977 1 2
    3 T2 3154 3019 0.957 1 3
    4 T2 1343 1306 0.972 1 4
H2 Hydrogen diatomic 1 Σg 4410 4401 0.998 2 5
CS carbon monosulfide 1 Σ 1253 1285 1.025 3 6
HO2 Hydroperoxy radical 1 A' 3674 3436 0.935 4 7
    2 A' 1430 1392 0.973 4 8
    3 A' 1116 1098 0.983 4 9
CH Methylidyne 1 Σ 2834 2861 1.010 5 10
    1 Σ 3109 3145 1.012 5 11
OH Hydroxyl radical 1 Σ 3738 3738 1.000 6 12
HCl Hydrogen chloride 1 Σ 3000 2991 0.997 7 13
HF Hydrogen fluoride 1 Σ 4178 4138 0.991 8 14
NH3 Ammonia 1 A1 3469 3337 0.962 9 15
    2 A1 1112 950 0.854 9 16
    3 E 3594 3444 0.958 9 17
    4 E 1688 1627 0.964 9 18
H2O Water 1 A1 3838 3657 0.953 10 19
    2 A1 1668 1595 0.956 10 20
    3 B2 3943 3756 0.953 10 21
H2S Hydrogen sulfide 1 A1 2717 2615 0.963 11 22
    2 A1 1204 1183 0.983 11 23
    3 B2 2733 2626 0.961 11 24
AlH3 aluminum trihydride 1 A1' 1940 1900 0.980 12 25
    2 A2" 717 698 0.973 12 26
    3 E' 1946 1883 0.967 12 27
    4 E' 791 783 0.990 12 28
PH3 Phosphine 1 A1 2411 2323 0.963 13 29
    2 A1 1018 992 0.974 13 30
    3 E 2420 2328 0.962 13 31
    4 E 1142 1118 0.979 13 32
SiH4 Silane 1 A1 2250 2187 0.972 14 33
    2 E 984 975 0.991 14 34
    3 T2 2258 2191 0.970 14 35
    4 T2 930 914 0.982 14 36
BH3 boron trihydride 2 A2" 1160 1148 0.989 15 37
    3 E' 2697 2602 0.964 15 38
    4 E' 1223 1197 0.979 15 39
PH2 Phosphino radical 1 A1 2385 2310 0.968 16 40
    2 A1 1124 1102 0.980 16 41
SiH3 Silyl radical 1 A1 2218 2136 0.963 17 42
    2 A1 775 728 0.940 17 43
    3 E 2253 2185 0.970 17 44
    4 E 940 922 0.981 17 45
BH Boron monohydride 1 Σ 2350 2367 1.007 18 46
NH2 Amino radical 1 A1 3364 3219 0.957 19 47
    2 A1 1558 1497 0.961 19 48
    3 B2 3456 3301 0.955 19 49
NH Imidogen 1 Σ 3264 3283 1.006 20 50
    1 Σ 3322 3314 0.998 20 51
SiH Silylidyne 1 Σ 2031 2043 1.006 21 52
SiH2 silicon dihydride 1 A1 2062 1996 0.968 22 53
    2 A1 1020 999 0.980 22 54
    3 B2 2060 1993 0.967 22 55
SH Mercapto radical 1 Σ 2687 2696 1.003 23 56
PH phosphorus monohydride 1 Σ 2352 2364 1.005 24 57
    1 Σ 2372 2415 1.018 24 58
AlH aluminum monohydride 1 Σ 1681 1682 1.001 25 59
BH2 boron dihydride 2 A1 1018 954 0.937 26 60
AlH2 aluminum dihydride 1 A1 1847 1770 0.958 27 61
    2 A1 765 760 0.993 27 62
    3 B2 1883 1807 0.960 27 63

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.

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