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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at MP3/3-21G*
Scale factor How many Source
Molecules Vibrations
0.965 ± 0.046 23 105 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
H2 Hydrogen diatomic 1 Σg 4478 4161 0.929 1 1
LiH Lithium Hydride 1 Σ 1351 1360 1.006 2 2
Na2 Sodium diatomic 1 Σg 129 158 1.220 3 3
N2 Nitrogen diatomic 1 Σg 2391 2330 0.974 4 4
OH Hydroxyl radical 1 Σ 3334 3570 1.071 5 5
CO Carbon monoxide 1 Σ 2195 2143 0.977 6 6
HF Hydrogen fluoride 1 Σ 3753 3961 1.056 7 7
F2 Fluorine diatomic 1 Σg 1033 894 0.866 8 8
HCl Hydrogen chloride 1 Σ 3002 2886 0.961 9 9
Cl2 Chlorine diatomic 1 Σg 501 554 1.106 10 10
H2O Water 1 A1 3513 3657 1.041 11 11
    2 A1 1737 1595 0.918 11 12
    3 B2 3653 3756 1.028 11 13
CO2 Carbon dioxide 1 Σg 1356 1333 0.983 12 14
    2 Σu 2369 2349 0.991 12 15
    3 Πu 573 667 1.164 12 16
SO2 Sulfur dioxide 1 A1 1213 1151 0.950 13 17
    2 A1 546 518 0.947 13 18
    3 B2 1448 1362 0.940 13 19
C2H2 Acetylene 1 Σg 3541 3374 0.953 14 20
    2 Σg 2089 1974 0.945 14 21
    3 Σu 3434 3289 0.958 14 22
    4 Πg 555 612 1.103 14 23
    5 Πu 756 730 0.966 14 24
NH3 Ammonia 1 A1 3429 3337 0.973 15 25
    2 A1 958 950 0.992 15 26
    3 E 3571 3444 0.964 15 27
    4 E 1796 1627 0.906 15 28
H2CO Formaldehyde 1 A1 2994 2782 0.929 16 29
    2 A1 1750 1746 0.998 16 30
    3 A1 1600 1500 0.937 16 31
    4 B1 1211 1167 0.964 16 32
    5 B2 3058 2843 0.930 16 33
    6 B2 1310 1249 0.953 16 34
BF3 Borane, trifluoro- 1 A1' 920 888 0.965 17 35
    2 A2" 672 691 1.029 17 36
    3 E' 1600 1449 0.906 17 37
    4 E' 487 480 0.986 17 38
AlF3 Aluminum trifluoride 1 A1' 767 690 0.900 18 39
    2 A2" 307 297 0.969 18 40
    3 E' 1080 935 0.866 18 41
    4 E' 256 263 1.029 18 42
CH4 Methane 1 A1 3069 2917 0.950 19 43
    2 E 1654 1534 0.927 19 44
    3 T2 3169 3019 0.953 19 45
    4 T2 1449 1306 0.901 19 46
C2H4 Ethylene 1 Ag 3179 3026 0.952 20 47
    2 Ag 1714 1623 0.947 20 48
    3 Ag 1438 1342 0.933 20 49
    4 Au 1078 1023 0.949 20 50
    5 B1u 3159 2989 0.946 20 51
    6 B1u 1567 1444 0.921 20 52
    7 B2g 976 940 0.962 20 53
    8 B2u 3257 3105 0.953 20 54
    9 B2u 892 826 0.926 20 55
    10 B3g 3228 3086 0.956 20 56
    11 B3g 1302 1217 0.935 20 57
    12 B3u 996 949 0.953 20 58
C2H6 Ethane 1 A1g 3075 2954 0.961 21 59
    2 A1g 1495 1388 0.928 21 60
    3 A1g 972 995 1.024 21 61
    4 A1u 318 289 0.908 21 62
    5 A2u 3074 2896 0.942 21 63
    6 A2u 1497 1379 0.921 21 64
    7 Eg 3124 2969 0.950 21 65
    8 Eg 1598 1468 0.919 21 66
    9 Eg 1289 1190 0.923 21 67
    10 Eu 3148 2985 0.948 21 68
    11 Eu 1601 1469 0.918 21 69
    12 Eu 870 822 0.945 21 70
C3H6 Cyclopropane 1 A1' 3199 3038 0.950 22 71
    2 A1' 1580 1479 0.936 22 72
    3 A1' 1150 1188 1.033 22 73
    4 A1" 1207 1126 0.933 22 74
    5 A2' 1167 1070 0.917 22 75
    6 A2" 3290 3103 0.943 22 76
    7 A2" 880 854 0.970 22 77
    8 E' 3188 3025 0.949 22 78
    9 E' 1556 1438 0.924 22 79
    10 E' 1146 1029 0.898 22 80
    11 E' 858 866 1.009 22 81
    12 E" 3267 3082 0.943 22 82
    13 E" 1255 1188 0.947 22 83
    14 E" 790 739 0.935 22 84
CH2CHCH3 Propene 1 A' 3238 3090 0.954 23 85
    2 A' 3167 3013 0.951 23 86
    3 A' 3156 2991 0.948 23 87
    4 A' 3129 2954 0.944 23 88
    5 A' 3061 2871 0.938 23 89
    6 A' 1728 1650 0.955 23 90
    7 A' 1592 1470 0.923 23 91
    8 A' 1529 1420 0.929 23 92
    9 A' 1491 1378 0.924 23 93
    10 A' 1386 1297 0.936 23 94
    11 A' 1234 1171 0.949 23 95
    12 A' 1008 963 0.955 23 96
    13 A' 909 920 1.012 23 97
    14 A' 443 428 0.965 23 98
    15 A" 3114 2954 0.948 23 99
    16 A" 1579 1443 0.914 23 100
    17 A" 1131 1045 0.924 23 101
    18 A" 1044 991 0.949 23 102
    19 A" 959 912 0.951 23 103
    20 A" 594 578 0.972 23 104
    21 A" 188 174 0.928 23 105

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 70 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 50 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 30 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 10 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