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

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at PM3
Scale factor How many Source
Molecules Vibrations
0.974 ± 0.077 227 2560 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH3OH Methyl alcohol 1 A' 3895 3681 0.945 1 1
    2 A' 3141 3000 0.955 1 2
    3 A' 3068 2844 0.927 1 3
    4 A' 1408 1477 1.049 1 4
    5 A' 1366 1455 1.066 1 5
    6 A' 1361 1345 0.988 1 6
    7 A' 1163 1060 0.911 1 7
    8 A' 988 1033 1.046 1 8
    9 A" 3036 2960 0.975 1 9
    10 A" 1366 1477 1.081 1 10
    11 A" 1020 1165 1.142 1 11
    12 A" 283 200 0.706 1 12
C2H6 Ethane 1 A1g 3186 2896 0.909 2 13
    2 A1g 1444 1388 0.961 2 14
    3 A1g 1138 995 0.874 2 15
    4 A1u 224 289 1.292 2 16
    5 A2u 3185 2915 0.915 2 17
    6 A2u 1359 1370 1.008 2 18
    7 Eg 3076 2969 0.965 2 19
    8 Eg 1414 1468 1.038 2 20
    9 Eg 1120 1190 1.063 2 21
    10 Eu 3089 2974 0.963 2 22
    11 Eu 1408 1460 1.037 2 23
    12 Eu 878 822 0.936 2 24
HCN Hydrogen cyanide 1 Σ 3297 3312 1.005 3 25
    2 Σ 2286 2089 0.914 3 26
    3 Π 837 712 0.851 3 27
CH3CHClCH3 Propane, 2-chloro- 1 A' 3179 3005 0.945 4 28
    2 A' 3087 2955 0.957 4 29
    3 A' 3081 2927 0.950 4 30
    4 A' 2924 2878 0.984 4 31
    5 A' 1407 1472 1.046 4 32
    6 A' 1395 1454 1.042 4 33
    7 A' 1392 1390 0.998 4 34
    8 A' 1198 1270 1.060 4 35
    9 A' 1148 1163 1.013 4 36
    10 A' 1050 1065 1.015 4 37
    11 A' 958 888 0.927 4 38
    12 A' 605 633 1.047 4 39
    13 A' 447 418 0.936 4 40
    14 A' 337 336 0.998 4 41
    15 A' 170 253 1.486 4 42
    16 A" 3180 2997 0.943 4 43
    17 A" 3085 2985 0.967 4 44
    18 A" 3082 2947 0.956 4 45
    19 A" 1416 1472 1.039 4 46
    20 A" 1400 1454 1.039 4 47
    21 A" 1392 1377 0.989 4 48
    22 A" 1292 1334 1.032 4 49
    23 A" 1128 1123 0.996 4 50
    24 A" 961 972 1.011 4 51
    25 A" 945 936 0.990 4 52
    26 A" 312 317 1.016 4 53
    27 A" 155 276 1.785 4 54
C5H6 1,3-Cyclopentadiene 1 A1 3159 3091 0.979 5 55
    2 A1 3137 3075 0.980 5 56
    3 A1 3052 2886 0.946 5 57
    4 A1 1718 1500 0.873 5 58
    5 A1 1419 1378 0.971 5 59
    6 A1 1362 1365 1.002 5 60
    7 A1 1206 1106 0.917 5 61
    8 A1 1090 994 0.912 5 62
    9 A1 1010 915 0.906 5 63
    10 A1 798 802 1.005 5 64
    11 A2 1036 1100 1.061 5 65
    12 A2 961 941 0.979 5 66
    13 A2 793 700 0.883 5 67
    14 A2 478 516 1.080 5 68
    15 B1 2986 2900 0.971 5 69
    16 B1 986 925 0.938 5 70
    17 B1 875 891 1.018 5 71
    18 B1 709 664 0.936 5 72
    19 B1 344 350 1.018 5 73
    20 B2 3149 3105 0.986 5 74
    21 B2 3134 3043 0.971 5 75
    22 B2 1784 1580 0.886 5 76
    23 B2 1350 1292 0.957 5 77
    24 B2 1219 1239 1.016 5 78
    25 B2 1088 1090 1.002 5 79
    26 B2 1021 959 0.939 5 80
    27 B2 825 805 0.976 5 81
BeO beryllium oxide 1 Σ 1443 1457 1.010 6 82
CH Methylidyne 1 Σ 3285 3145 0.957 7 83
N2 Nitrogen diatomic 1 Σg 2641 2359 0.893 8 84
H2O Water 1 A1 3990 3657 0.917 9 85
    2 A1 1741 1595 0.916 9 86
    3 B2 3869 3756 0.971 9 87
Cl2 Chlorine diatomic 1 Σg 596 560 0.939 10 88
AlF3 Aluminum trifluoride 1 A1' 794 690 0.869 11 89
    2 A2" 169 297 1.757 11 90
    3 E' 1073 935 0.872 11 91
    4 E' 210 263 1.250 11 92
P2 Phosphorus diatomic 1 Σg 555 781 1.406 12 93
AlCl Aluminum monochloride 1 Σ 420 482 1.146 13 94
BeH beryllium monohydride 1 Σ 2680 2061 0.769 14 95
SiH2 silicon dihydride 1 A1 1942 1996 1.028 15 96
    2 A1 900 999 1.110 15 97
    3 B2 1933 1993 1.031 15 98
PH phosphorus monohydride 1 Σ 1613 2415 1.497 16 99
ClO Monochlorine monoxide 1 Σ 862 854 0.990 17 100
SCl sulfur monochloride 1 Σ 604 575 0.951 18 101

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.

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