return to home page

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

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at CISD/6-31G**
Scale factor How many Source
Molecules Vibrations
0.918 ± 0.017 14 172 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
HCN Hydrogen cyanide 1 Σ 3570 3312 0.928 1 1
    2 Σ 2253 2089 0.927 1 2
    3 Π 767 712 0.928 1 3
C3H8 Propane 1 A1 3243 2977 0.918 2 4
    2 A1 3162 2962 0.937 2 5
    3 A1 3159 2887 0.914 2 6
    4 A1 1601 1476 0.922 2 7
    5 A1 1578 1462 0.927 2 8
    6 A1 1509 1392 0.922 2 9
    7 A1 1243 1158 0.932 2 10
    8 A1 922 869 0.942 2 11
    9 A1 382 369 0.965 2 12
    10 A2 3232 2967 0.918 2 13
    11 A2 1578 1451 0.920 2 14
    12 A2 1385 1278 0.923 2 15
    13 A2 953 940 0.987 2 16
    14 A2 233 216 0.928 2 17
    15 B1 3242 2973 0.917 2 18
    16 B1 3197 2968 0.928 2 19
    17 B1 1595 1472 0.923 2 20
    18 B1 1286 1192 0.927 2 21
    19 B1 782 748 0.957 2 22
    20 B1 291 268 0.921 2 23
    21 B2 3241 2968 0.916 2 24
    22 B2 3156 2887 0.915 2 25
    23 B2 1585 1464 0.924 2 26
    24 B2 1500 1378 0.919 2 27
    25 B2 1446 1338 0.925 2 28
    26 B2 1120 1054 0.941 2 29
    27 B2 977 922 0.943 2 30
CH3CH2NH2 Ethylamine 1 A' 3645 3345 0.918 3 31
    2 A' 3239 2985 0.922 3 32
    3 A' 3174 2840 0.895 3 33
    4 A' 3153 2860 0.907 3 34
    5 A' 1746 1622 0.929 3 35
    6 A' 1594 1487 0.933 3 36
    7 A' 1576 1465 0.930 3 37
    8 A' 1501 1378 0.918 3 38
    9 A' 1459 1397 0.957 3 39
    10 A' 1216 1016 0.836 3 40
    11 A' 1136 1086 0.956 3 41
    12 A' 950 892 0.939 3 42
    13 A' 921 773 0.840 3 43
    14 A' 419 403 0.961 3 44
    15 A" 3734 3412 0.914 3 45
    16 A" 3240 2924 0.902 3 46
    17 A" 3212 2906 0.905 3 47
    18 A" 1583 1455 0.919 3 48
    19 A" 1458 1238 0.849 3 49
    20 A" 1341 1293 0.964 3 50
    21 A" 1052 1117 1.062 3 51
    22 A" 811 816 1.007 3 52
    23 A" 319 259 0.811 3 53
    24 A" 271 218 0.803 3 54
CH3SCH3 Dimethyl sulfide 1 A1 3277 2998 0.915 4 55
    2 A1 3170 2930 0.924 4 56
    3 A1 1576 1444 0.916 4 57
    4 A1 1473 1331 0.903 4 58
    5 A1 1121 973 0.868 4 59
    6 A1 748 695 0.929 4 60
    7 A1 282 282 1.000 4 61
    8 A2 3263 2952 0.905 4 62
    9 A2 1548 1420 0.917 4 63
    10 A2 1021 919 0.900 4 64
    12 B1 3258 2970 0.912 4 65
    13 B1 1558 1439 0.923 4 66
    14 B1 1058 973 0.919 4 67
    15 B1 194 182 0.938 4 68
    16 B2 3278 2998 0.915 4 69
    17 B2 3172 2930 0.924 4 70
    18 B2 1567 1444 0.921 4 71
    19 B2 1448 1315 0.908 4 72
    20 B2 975 903 0.926 4 73
    21 B2 806 743 0.921 4 74
CH2CHCH3 Propene 1 A' 3366 3090 0.918 5 75
    2 A' 3283 3013 0.918 5 76
    3 A' 3270 2991 0.915 5 77
    4 A' 3246 2954 0.910 5 78
    5 A' 3154 2871 0.910 5 79
    6 A' 1815 1650 0.909 5 80
    7 A' 1581 1470 0.930 5 81
    8 A' 1535 1420 0.925 5 82
    9 A' 1491 1378 0.924 5 83
    10 A' 1387 1297 0.935 5 84
    11 A' 1250 1171 0.937 5 85
    12 A' 990 963 0.972 5 86
    13 A' 971 920 0.948 5 87
    14 A' 438 428 0.977 5 88
    15 A" 3221 2954 0.917 5 89
    16 A" 1566 1443 0.921 5 90
    17 A" 1129 1045 0.926 5 91
    18 A" 1074 991 0.922 5 92
    19 A" 987 912 0.924 5 93
    20 A" 610 578 0.947 5 94
    21 A" 202 174 0.862 5 95
CH3OCH3 Dimethyl ether 1 A1 3270 2996 0.916 6 96
    2 A1 3125 2817 0.901 6 97
    3 A1 1609 1464 0.910 6 98
    4 A1 1580 1452 0.919 6 99
    5 A1 1338 1244 0.930 6 100
    6 A1 1010 928 0.919 6 101
    7 A1 433 418 0.965 6 102
    8 A2 3179 2952 0.929 6 103
    9 A2 1574 1464 0.930 6 104
    10 A2 1222 1150 0.941 6 105
    11 A2 212 203 0.959 6 106
    12 B1 3177 2925 0.921 6 107
    13 B1 1585 1464 0.924 6 108
    14 B1 1260 1179 0.936 6 109
    15 B1 263 242 0.920 6 110
    16 B2 3268 2996 0.917 6 111
    17 B2 3113 2817 0.905 6 112
    18 B2 1592 1464 0.920 6 113
    19 B2 1542 1452 0.941 6 114
    20 B2 1286 1227 0.954 6 115
    21 B2 1184 1102 0.931 6 116
C2H5N Aziridine 1 A' 3681 3338 0.907 7 117
    2 A' 3351 3079 0.919 7 118
    3 A' 3259 3015 0.925 7 119
    4 A' 1626 1482 0.912 7 120
    5 A' 1360 1237 0.909 7 121
    6 A' 1322 1211 0.916 7 122
    7 A' 1200 1090 0.909 7 123
    8 A' 1057 998 0.944 7 124
    9 A' 941 856 0.910 7 125
    10 A' 820 773 0.943 7 126
    11 A" 3338 3079 0.922 7 127
    12 A" 3249 3015 0.928 7 128
    13 A" 1585 1463 0.923 7 129
    14 A" 1342 1268 0.945 7 130
    15 A" 1222 1131 0.926 7 131
    16 A" 1187 1095 0.922 7 132
    17 A" 965 904 0.937 7 133
    18 A" 943 817 0.867 7 134
CH3SSCH3 Disulfide, dimethyl 1 A 3299 2990 0.906 8 135
    2 A 3285 2983 0.908 8 136
    3 A 3189 2913 0.913 8 137
    4 A 1569 1426 0.909 8 138
    5 A 1556 1419 0.912 8 139
    6 A 1464 1311 0.895 8 140
    7 A 1050 955 0.909 8 141
    8 A 1046 949 0.908 8 142
    9 A 766 694 0.906 8 143
    10 A 546 509 0.932 8 144
    11 A 247 240 0.970 8 145
    12 A 164 134 0.816 8 146
    13 A 100 117 1.173 8 147
    14 B 3299 2990 0.906 8 148
    15 B 3284 2983 0.908 8 149
    16 B 3188 2915 0.915 8 150
    17 B 1573 1430 0.909 8 151
    18 B 1549 1415 0.913 8 152
    19 B 1456 1303 0.895 8 153
    20 B 1051 955 0.909 8 154
    21 B 1041 949 0.912 8 155
    22 B 761 691 0.908 8 156
    23 B 278 274 0.985 8 157
    24 B 175 134 0.767 8 158
CS carbon monosulfide 1 Σ 1357 1285 0.947 9 159
HCP HCP 1 Σ 3476 3217 0.925 10 160
    2 Σ 1374 1278 0.930 10 161
    3 Π 737 674 0.915 10 162
HOCl hypochlorous acid 1 A' 3943 3609 0.915 11 163
    2 A' 1331 1239 0.931 11 164
    3 A' 776 724 0.934 11 165
Si2 Silicon diatomic 1 Σg 569 511 0.898 12 166
HOF Hypofluorous acid 1 A' 3927 3537 0.901 13 167
    2 A' 1450 1393 0.961 13 168
    3 A' 1028 886 0.862 13 169
HBO Boron hydride oxide 1 Σ 2998 2850 0.951 14 170
    2 Σ 1915 1826 0.954 14 171
    3 Π 793 756 0.953 14 172

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.

100
80
60
40
20
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