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