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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at MP3/6-31G**
Scale factor How many Source
Molecules Vibrations
0.935 ± 0.020 23 105 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
H2 Hydrogen diatomic 1 Σg 4573 4161 0.910 1 1
LiH Lithium Hydride 1 Σ 1406 1360 0.967 2 2
Na2 Sodium diatomic 1 Σg 159 158 0.990 3 3
N2 Nitrogen diatomic 1 Σg 2533 2330 0.920 4 4
OH Hydroxyl radical 1 Σ 3832 3570 0.932 5 5
CO Carbon monoxide 1 Σ 2305 2143 0.930 6 6
HF Hydrogen fluoride 1 Σ 4235 3961 0.936 7 7
F2 Fluorine diatomic 1 Σg 1009 894 0.886 8 8
HCl Hydrogen chloride 1 Σ 3102 2886 0.930 9 9
Cl2 Chlorine diatomic 1 Σg 531 554 1.044 10 10
H2O Water 1 A1 3940 3657 0.928 11 11
    2 A1 1704 1595 0.936 11 12
    3 B2 4057 3756 0.926 11 13
CO2 Carbon dioxide 1 Σg 1432 1333 0.931 12 14
    2 Σu 2493 2349 0.942 12 15
    3 Πu 672 667 0.993 12 16
SO2 Sulfur dioxide 1 A1 1235 1151 0.932 13 17
    2 A1 533 518 0.971 13 18
    3 B2 1447 1362 0.941 13 19
C2H2 Acetylene 1 Σg 3611 3374 0.934 14 20
    2 Σg 2115 1974 0.933 14 21
    3 Σu 3513 3289 0.936 14 22
    4 Πg 494 612 1.238 14 23
    5 Πu 771 730 0.947 14 24
NH3 Ammonia 1 A1 3580 3337 0.932 15 25
    2 A1 1136 950 0.836 15 26
    3 E 3719 3444 0.926 15 27
    4 E 1736 1627 0.937 15 28
H2CO Formaldehyde 1 A1 3049 2782 0.912 16 29
    2 A1 1879 1746 0.929 16 30
    3 A1 1608 1500 0.933 16 31
    4 B1 1228 1167 0.951 16 32
    5 B2 3129 2843 0.909 16 33
    6 B2 1315 1249 0.950 16 34
BF3 Borane, trifluoro- 1 A1' 906 888 0.980 17 35
    2 A2" 710 691 0.973 17 36
    3 E' 1522 1449 0.952 17 37
    4 E' 488 480 0.985 17 38
AlF3 Aluminum trifluoride 1 A1' 723 690 0.955 18 39
    2 A2" 307 297 0.966 18 40
    3 E' 1009 935 0.927 18 41
    4 E' 264 263 0.996 18 42
CH4 Methane 1 A1 3136 2917 0.930 19 43
    2 E 1622 1534 0.946 19 44
    3 T2 3270 3019 0.923 19 45
    4 T2 1410 1306 0.926 19 46
C2H4 Ethylene 1 Ag 3262 3026 0.928 20 47
    2 Ag 1754 1623 0.925 20 48
    3 Ag 1421 1342 0.944 20 49
    4 Au 1084 1023 0.944 20 50
    5 B1u 3244 2989 0.921 20 51
    6 B1u 1532 1444 0.942 20 52
    7 B2g 947 940 0.992 20 53
    8 B2u 3354 3105 0.926 20 54
    9 B2u 851 826 0.971 20 55
    10 B3g 3331 3086 0.926 20 56
    11 B3g 1275 1217 0.955 20 57
    12 B3u 995 949 0.954 20 58
C2H6 Ethane 1 A1g 3141 2954 0.941 21 59
    2 A1g 1496 1388 0.928 21 60
    3 A1g 1048 995 0.950 21 61
    4 A1u 332 289 0.871 21 62
    5 A2u 3140 2896 0.922 21 63
    6 A2u 1466 1379 0.941 21 64
    7 Eg 3211 2969 0.925 21 65
    8 Eg 1567 1468 0.937 21 66
    9 Eg 1273 1190 0.934 21 67
    10 Eu 3232 2985 0.924 21 68
    11 Eu 1572 1469 0.934 21 69
    12 Eu 847 822 0.971 21 70
C3H6 Cyclopropane 1 A1' 3253 3038 0.934 22 71
    2 A1' 1599 1479 0.925 22 72
    3 A1' 1264 1188 0.940 22 73
    4 A1" 1207 1126 0.933 22 74
    5 A2' 1133 1070 0.944 22 75
    6 A2" 3345 3103 0.928 22 76
    7 A2" 885 854 0.965 22 77
    8 E' 3242 3025 0.933 22 78
    9 E' 1540 1438 0.934 22 79
    10 E' 1129 1029 0.912 22 80
    11 E' 934 866 0.927 22 81
    12 E" 3327 3082 0.926 22 82
    13 E" 1262 1188 0.941 22 83
    14 E" 771 739 0.959 22 84
CH2CHCH3 Propene 1 A' 3337 3090 0.926 23 85
    2 A' 3252 3013 0.927 23 86
    3 A' 3241 2991 0.923 23 87
    4 A' 3220 2954 0.917 23 88
    5 A' 3128 2871 0.918 23 89
    6 A' 1780 1650 0.927 23 90
    7 A' 1562 1470 0.941 23 91
    8 A' 1512 1420 0.939 23 92
    9 A' 1469 1378 0.938 23 93
    10 A' 1365 1297 0.950 23 94
    11 A' 1231 1171 0.951 23 95
    12 A' 975 963 0.987 23 96
    13 A' 959 920 0.959 23 97
    14 A' 431 428 0.994 23 98
    15 A" 3198 2954 0.924 23 99
    16 A" 1545 1443 0.934 23 100
    17 A" 1106 1045 0.945 23 101
    18 A" 1047 991 0.947 23 102
    19 A" 941 912 0.970 23 103
    20 A" 593 578 0.974 23 104
    21 A" 198 174 0.880 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 80 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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