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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 ± 0.016 19 193 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
Si2 Silicon diatomic 1 Σg 569 507 0.890 1 1
CO Carbon monoxide 1 Σ 2264 2143 0.947 2 2
CS carbon monosulfide 1 Σ 1357 1272 0.938 3 3
HCN Hydrogen cyanide 1 Σ 3570 3312 0.928 4 4
    2 Σ 2253 2089 0.927 4 5
    3 Π 767 712 0.928 4 6
HCP Phosphaethyne 1 Σ 3476 3217 0.925 5 7
    2 Σ 1374 1278 0.930 5 8
    3 Π 737 674 0.915 5 9
HBO Boron hydride oxide 1 Σ 2998 2850 0.951 6 10
    2 Σ 1915 1826 0.954 6 11
    3 Π 793 756 0.953 6 12
HO2 Hydroperoxy radical 1 A' 3831 3436 0.897 7 13
    2 A' 1497 1392 0.930 7 14
    3 A' 1201 1098 0.914 7 15
HOF Hypofluorous acid 1 A' 3927 3578 0.911 8 16
    2 A' 1450 1362 0.940 8 17
    3 A' 1028 893 0.869 8 18
HOCl hypochlorous acid 1 A' 3943 3609 0.915 9 19
    2 A' 1331 1239 0.931 9 20
    3 A' 776 724 0.934 9 21
BF3 Borane, trifluoro- 1 A1' 915 888 0.970 10 22
    2 A2" 716 691 0.965 10 23
    3 E' 1536 1449 0.943 10 24
    4 E' 492 480 0.976 10 25
AlF3 Aluminum trifluoride 1 A1' 728 690 0.948 11 26
    2 A2" 309 297 0.962 11 27
    3 E' 1015 935 0.921 11 28
    4 E' 265 263 0.992 11 29
NH2OH hydroxylamine 1 A' 3995 3650 0.914 12 30
    2 A' 3594 3294 0.916 12 31
    3 A' 1743 1605 0.920 12 32
    4 A' 1467 1353 0.923 12 33
    5 A' 1214 1115 0.919 12 34
    6 A' 1016 895 0.881 12 35
    7 A" 3686 3359 0.911 12 36
    8 A" 1384 1295 0.935 12 37
    9 A" 420 386 0.918 12 38
C2H5N Aziridine 1 A' 3681 3338 0.907 13 39
    2 A' 3351 3079 0.919 13 40
    3 A' 3259 3015 0.925 13 41
    4 A' 1626 1482 0.912 13 42
    5 A' 1360 1237 0.909 13 43
    6 A' 1322 1211 0.916 13 44
    7 A' 1200 1090 0.909 13 45
    8 A' 1057 998 0.944 13 46
    9 A' 941 856 0.910 13 47
    10 A' 820 773 0.943 13 48
    11 A" 3338 3079 0.922 13 49
    12 A" 3249 3015 0.928 13 50
    13 A" 1585 1463 0.923 13 51
    14 A" 1342 1268 0.945 13 52
    15 A" 1222 1131 0.926 13 53
    16 A" 1187 1095 0.922 13 54
    17 A" 965 904 0.937 13 55
    18 A" 943 817 0.867 13 56
CH2CHCH3 Propene 1 A' 3366 3090 0.918 14 57
    2 A' 3283 3013 0.918 14 58
    3 A' 3270 2991 0.915 14 59
    4 A' 3246 2954 0.910 14 60
    5 A' 3154 2871 0.910 14 61
    6 A' 1815 1650 0.909 14 62
    7 A' 1581 1470 0.930 14 63
    8 A' 1535 1420 0.925 14 64
    9 A' 1491 1378 0.924 14 65
    10 A' 1387 1297 0.935 14 66
    11 A' 1250 1171 0.937 14 67
    12 A' 990 963 0.972 14 68
    13 A' 971 920 0.948 14 69
    14 A' 438 428 0.977 14 70
    15 A" 3221 2954 0.917 14 71
    16 A" 1566 1443 0.921 14 72
    17 A" 1129 1045 0.926 14 73
    18 A" 1074 991 0.922 14 74
    19 A" 987 912 0.924 14 75
    20 A" 610 578 0.947 14 76
    21 A" 202 174 0.862 14 77
CH3OCH3 Dimethyl ether 1 A1 3270 2996 0.916 15 78
    2 A1 3125 2817 0.901 15 79
    3 A1 1609 1464 0.910 15 80
    4 A1 1580 1452 0.919 15 81
    5 A1 1338 1244 0.930 15 82
    6 A1 1010 928 0.919 15 83
    7 A1 433 418 0.965 15 84
    8 A2 3179 2952 0.929 15 85
    9 A2 1574 1464 0.930 15 86
    10 A2 1222 1150 0.941 15 87
    11 A2 212 203 0.959 15 88
    12 B1 3177 2925 0.921 15 89
    13 B1 1585 1464 0.924 15 90
    14 B1 1260 1179 0.936 15 91
    15 B1 263 242 0.920 15 92
    16 B2 3268 2996 0.917 15 93
    17 B2 3113 2817 0.905 15 94
    18 B2 1592 1464 0.920 15 95
    19 B2 1542 1452 0.941 15 96
    20 B2 1286 1227 0.954 15 97
    21 B2 1184 1102 0.931 15 98
CH3SCH3 Dimethyl sulfide 1 A1 3277 2997 0.914 16 99
    2 A1 3170 2925 0.923 16 100
    3 A1 1576 1447 0.918 16 101
    4 A1 1473 1337 0.908 16 102
    5 A1 1121 1030 0.919 16 103
    6 A1 748 695 0.929 16 104
    7 A1 282 280 0.993 16 105
    8 A2 3263 2970 0.910 16 106
    9 A2 1548 1427 0.922 16 107
    10 A2 1021 946 0.926 16 108
    11 A2 184 175 0.949 16 109
    12 B1 3258 2970 0.912 16 110
    13 B1 1558 1439 0.923 16 111
    14 B1 1058 973 0.919 16 112
    15 B1 194 183 0.943 16 113
    16 B2 3278 2999 0.915 16 114
    17 B2 3172 2919 0.920 16 115
    18 B2 1567 1442 0.920 16 116
    19 B2 1448 1315 0.908 16 117
    20 B2 975 903 0.926 16 118
    21 B2 806 742 0.920 16 119
CH3CH2NH2 Ethylamine 1 A' 3645 3345 0.918 17 120
    2 A' 3239 2985 0.922 17 121
    3 A' 3174 2840 0.895 17 122
    4 A' 3153 2860 0.907 17 123
    5 A' 1746 1622 0.929 17 124
    6 A' 1594 1487 0.933 17 125
    7 A' 1576 1465 0.930 17 126
    8 A' 1501 1378 0.918 17 127
    9 A' 1459 1397 0.957 17 128
    10 A' 1216 1016 0.836 17 129
    11 A' 1136 1086 0.956 17 130
    12 A' 950 892 0.939 17 131
    13 A' 921 773 0.840 17 132
    14 A' 419 403 0.961 17 133
    15 A" 3734 3412 0.914 17 134
    16 A" 3240 2924 0.902 17 135
    17 A" 3212 2906 0.905 17 136
    18 A" 1583 1455 0.919 17 137
    19 A" 1458 1238 0.849 17 138
    20 A" 1341 1293 0.964 17 139
    21 A" 1052 1117 1.062 17 140
    22 A" 811 816 1.007 17 141
    23 A" 319 259 0.811 17 142
    24 A" 271 218 0.803 17 143
CH3SSCH3 Disulfide, dimethyl 1 A 3299 2990 0.906 18 144
    2 A 3285 2983 0.908 18 145
    3 A 3189 2913 0.913 18 146
    4 A 1569 1426 0.909 18 147
    5 A 1556 1419 0.912 18 148
    6 A 1464 1311 0.895 18 149
    7 A 1050 955 0.909 18 150
    8 A 1046 949 0.908 18 151
    9 A 766 694 0.906 18 152
    10 A 546 509 0.932 18 153
    11 A 247 240 0.970 18 154
    12 A 164 134 0.816 18 155
    13 A 100 117 1.173 18 156
    14 B 3299 2990 0.906 18 157
    15 B 3284 2983 0.908 18 158
    16 B 3188 2915 0.915 18 159
    17 B 1573 1430 0.909 18 160
    18 B 1549 1415 0.913 18 161
    19 B 1456 1303 0.895 18 162
    20 B 1051 955 0.909 18 163
    21 B 1041 949 0.912 18 164
    22 B 761 691 0.908 18 165
    23 B 278 274 0.985 18 166
    24 B 175 134 0.767 18 167
C3H8 Propane 1 A1 3243 2977 0.918 19 168
    2 A1 3162 2962 0.937 19 169
    3 A1 3159 2887 0.914 19 170
    4 A1 1601 1476 0.922 19 171
    5 A1 1578 1462 0.927 19 172
    6 A1 1509 1392 0.922 19 173
    7 A1 1243 1158 0.932 19 174
    8 A1 922 869 0.942 19 175
    9 A1 382 369 0.965 19 176
    10 A2 3232 2967 0.918 19 177
    11 A2 1578 1451 0.920 19 178
    12 A2 1385 1278 0.923 19 179
    13 A2 953 940 0.987 19 180
    14 A2 233 216 0.928 19 181
    15 B1 3242 2973 0.917 19 182
    16 B1 3197 2968 0.929 19 183
    17 B1 1595 1472 0.923 19 184
    18 B1 1286 1192 0.927 19 185
    19 B1 782 748 0.957 19 186
    20 B1 291 268 0.921 19 187
    21 B2 3241 2968 0.916 19 188
    22 B2 3156 2887 0.915 19 189
    23 B2 1585 1464 0.924 19 190
    24 B2 1500 1378 0.919 19 191
    25 B2 1446 1338 0.925 19 192
    26 B2 1120 1054 0.941 19 193
    27 B2 977 922 0.943 19 194

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.

40 120 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 100 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 80 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 60 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 20 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