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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at MP4/6-311G**
Scale factor How many Source
Molecules Vibrations
0.970 ± 0.033 17 62 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
H2 Hydrogen diatomic 1 Σg 4456 4401 0.988 1 1
LiH Lithium Hydride 1 Σ 1425 1405 0.986 2 2
CH Methylidyne 1 Σ 3156 3145 0.996 3 3
N2 Nitrogen diatomic 1 Σg 2184 2359 1.080 4 4
CO Carbon monoxide 1 Σ 2010 2170 1.079 5 5
HF Hydrogen fluoride 1 Σ 4238 4138 0.977 6 6
F2 Fluorine diatomic 1 Σg 791 917 1.159 7 7
HCl Hydrogen chloride 1 Σ 3047 2991 0.982 8 8
H2O Water 1 A1 3880 3657 0.943 9 9
    2 A1 1680 1595 0.950 9 10
    3 B2 3978 3756 0.944 9 11
CO2 Carbon dioxide 1 Σg 1271 1333 1.049 10 12
    2 Σu 2368 2349 0.992 10 13
    3 Πu 635 667 1.050 10 14
SO2 Sulfur dioxide 1 A1 974 1151 1.182 11 15
    2 A1 472 518 1.097 11 16
    3 B2 1198 1362 1.136 11 17
C2H2 Acetylene 1 Σg 3522 3374 0.958 12 18
    2 Σg 1954 1974 1.010 12 19
    3 Σu 3431 3289 0.959 12 20
    4 Πg 514 612 1.190 12 21
    5 Πu 754 730 0.968 12 22
NH3 Ammonia 1 A1 3481 3337 0.959 13 23
    2 A1 1147 950 0.828 13 24
    3 E 3614 3444 0.953 13 25
    4 E 1672 1627 0.973 13 26
H2CO Formaldehyde 1 A1 2914 2782 0.955 14 27
    2 A1 1750 1746 0.998 14 28
    3 A1 1545 1500 0.971 14 29
    4 B1 1188 1167 0.983 14 30
    5 B2 2969 2843 0.957 14 31
    6 B2 1273 1249 0.981 14 32
CH4 Methane 1 A1 3042 2917 0.959 15 33
    2 E 1566 1534 0.980 15 34
    3 T2 3168 3019 0.953 15 35
    4 T2 1359 1306 0.961 15 36
C2H4 Ethylene 1 Ag 3160 3026 0.958 16 37
    2 Ag 1662 1623 0.976 16 38
    3 Ag 1367 1342 0.982 16 39
    4 Au 1048 1023 0.976 16 40
    5 B1u 3142 2989 0.951 16 41
    6 B1u 1474 1444 0.979 16 42
    7 B2g 892 940 1.053 16 43
    8 B2u 3253 3105 0.955 16 44
    9 B2u 820 826 1.007 16 45
    10 B3g 3226 3086 0.957 16 46
    11 B3g 1229 1217 0.990 16 47
    12 B3u 954 949 0.996 16 48
C3H6 Cyclopropane 1 A1' 3156 3038 0.962 17 49
    2 A1' 1536 1479 0.963 17 50
    3 A1' 1220 1188 0.974 17 51
    4 A1" 1173 1126 0.960 17 52
    5 A2' 1093 1070 0.979 17 53
    6 A2" 3253 3103 0.954 17 54
    7 A2" 865 854 0.987 17 55
    8 E' 3146 3025 0.961 17 56
    9 E' 1484 1438 0.969 17 57
    10 E' 1085 1029 0.948 17 58
    11 E' 896 866 0.966 17 59
    12 E" 3233 3082 0.953 17 60
    13 E" 1227 1188 0.968 17 61
    14 E" 754 739 0.980 17 62

How do we calculate the scaling factor? 2015 08 03 12:34

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 30 1 1 1 1 1 1 1 1 1 1 1 1 1 1
40 25 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 15 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 5 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