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

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at MP2=FULL/STO-3G
Scale factor How many Source
Molecules Vibrations
0.889 ± 0.073 19 103 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
H2CO Formaldehyde 1 A1 3267 2782 0.852 1 1
    2 A1 1800 1746 0.970 1 2
    3 A1 1607 1500 0.933 1 3
    4 B1 1130 1167 1.033 1 4
    5 B2 3400 2843 0.836 1 5
    6 B2 1297 1249 0.963 1 6
CH4 Methane 1 A1 3344 2917 0.872 2 7
    2 E 1810 1534 0.848 2 8
    3 T2 3602 3019 0.838 2 9
    4 T2 1577 1306 0.828 2 10
C2H4 Ethylene 1 Ag 3481 3026 0.869 3 11
    2 Ag 1810 1623 0.897 3 12
    3 Ag 1485 1342 0.904 3 13
    4 Au 1188 1023 0.861 3 14
    5 B1u 3451 2989 0.866 3 15
    6 B1u 1633 1444 0.884 3 16
    7 B2g 1000 940 0.939 3 17
    8 B2u 3625 3105 0.857 3 18
    9 B2u 880 826 0.938 3 19
    10 B3g 3612 3086 0.854 3 20
    11 B3g 1356 1217 0.898 3 21
    12 B3u 1039 949 0.913 3 22
C2H2 Acetylene 1 Σg 3791 3374 0.890 4 23
    2 Σg 2091 1974 0.944 4 24
    3 Σu 3677 3289 0.894 4 25
    4 Πg 715 612 0.856 4 26
    5 Πu 837 730 0.872 4 27
C3H6 Cyclopropane 1 A1' 3473 3038 0.875 5 28
    2 A1' 1695 1479 0.872 5 29
    3 A1' 1335 1188 0.890 5 30
    4 A1" 1302 1126 0.865 5 31
    5 A2' 1244 1070 0.860 5 32
    6 A2" 3619 3103 0.857 5 33
    7 A2" 902 854 0.946 5 34
    8 E' 3457 3025 0.875 5 35
    9 E' 1644 1438 0.875 5 36
    10 E' 1269 1029 0.811 5 37
    11 E' 1030 866 0.841 5 38
    12 E" 3613 3082 0.853 5 39
    13 E" 1340 1188 0.886 5 40
    14 E" 826 739 0.895 5 41
C3H2N2 Malononitrile 1 A1 3393 2935 0.865 6 42
    2 A1 2103 2275 1.082 6 43
    3 A1 1648 1395 0.847 6 44
    4 A1 918 890 0.969 6 45
    5 A1 577 582 1.009 6 46
    6 A1 141 167 1.182 6 47
    7 A2 1347 1220 0.906 6 48
    8 A2 343 367 1.069 6 49
    9 B1 3497 2968 0.849 6 50
    10 B1 1038 933 0.899 6 51
    11 B1 324 337 1.040 6 52
    12 B2 2110 2275 1.078 6 53
    13 B2 1460 1318 0.903 6 54
    14 B2 997 982 0.985 6 55
    15 B2 353 366 1.036 6 56
CO2 Carbon dioxide 1 Σg 1276 1333 1.045 7 57
    2 Σu 2598 2349 0.904 7 58
    3 Πu 478 667 1.395 7 59
C6H6 Fulvene 1 A1 3560 3088 0.868 8 60
    2 A1 3531 3051 0.864 8 61
    3 A1 3444 3008 0.873 8 62
    4 A1 1792 1632 0.911 8 63
    5 A1 1653 1486 0.899 8 64
    6 A1 1586 1449 0.913 8 65
    7 A1 1486 1342 0.903 8 66
    8 A1 1182 1082 0.916 8 67
    9 A1 1062 986 0.929 8 68
    10 A1 948 894 0.943 8 69
    11 A1 701 641 0.914 8 70
    12 A2 999     8 71
    13 A2 858     8 72
    14 A2 769 666 0.866 8 73
    15 A2 524 494 0.943 8 74
    16 B1 1014 926 0.913 8 75
    17 B1 974 907 0.931 8 76
    18 B1 836 769 0.920 8 77
    19 B1 641 613 0.956 8 78
    20 B1 201     8 79
    21 B2 3600     8 80
    22 B2 3552 3104 0.874 8 81
    23 B2 3525 3075 0.872 8 82
    24 B2 1714 1550 0.905 8 83
    25 B2 1456 1314 0.902 8 84
    26 B2 1347 1232 0.914 8 85
    27 B2 1183 1077 0.910 8 86
    28 B2 1035 952 0.920 8 87
    29 B2 852 795 0.933 8 88
    30 B2 350 350 1.000 8 89
CO Carbon monoxide 1 Σ 2010 2170 1.080 9 90
H2 Hydrogen diatomic 1 Σg 5245 4401 0.839 10 91
CH Methylidyne 1 Σ 3577 3145 0.879 11 92
SO2 Sulfur dioxide 1 A1 1050 1151 1.097 12 93
    2 A1 443 518 1.169 12 94
    3 B2 2047 1362 0.665 12 95
LiH Lithium Hydride 1 Σ 1781 1405 0.789 13 96
HCl Hydrogen chloride 1 Σ 3213 2991 0.931 14 97
HF Hydrogen fluoride 1 Σ 4144 4138 0.999 15 98
NH3 Ammonia 1 A1 3539 3337 0.943 16 99
    2 A1 1460 950 0.651 16 100
    3 E 3814 3444 0.903 16 101
    4 E 1991 1627 0.817 16 102
N2 Nitrogen diatomic 1 Σg 1669 2359 1.413 17 103
H2O Water 1 A1 3798 3657 0.963 18 104
    2 A1 2076 1595 0.768 18 105
    3 B2 4057 3756 0.926 18 106
F2 Fluorine diatomic 1 Σg 1464 917 0.626 19 107

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.

35
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