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