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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at MP4=FULL/TZVP
Scale factor How many Source
Molecules Vibrations
0.966 ± 0.042 20 89 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
LiH Lithium Hydride 1 Σ 1415 1360 0.961 1 1
Na2 Sodium diatomic 1 Σg 146 158 1.083 2 2
N2 Nitrogen diatomic 1 Σg 2195 2330 1.062 3 3
OH Hydroxyl radical 1 Σ 3742 3570 0.954 4 4
HF Hydrogen fluoride 1 Σ 4142 3961 0.956 5 5
F2 Fluorine diatomic 1 Σg 878 894 1.018 6 6
HCl Hydrogen chloride 1 Σ 3019 2886 0.956 7 7
AlCl Aluminum monochloride 1 Σ 490 478 0.975 8 8
Cl2 Chlorine diatomic 1 Σg 525 554 1.056 9 9
CO2 Carbon dioxide 1 Σg 1270 1333 1.050 10 10
    2 Σu 2354 2349 0.998 10 11
    3 Πu 642 667 1.040 10 12
SO2 Sulfur dioxide 1 A1 949 1151 1.213 11 13
    2 A1 453 518 1.144 11 14
    3 B2 1151 1362 1.183 11 15
C2H2 Acetylene 1 Σg 3534 3374 0.955 12 16
    2 Σg 1976 1974 0.999 12 17
    3 Σu 3444 3289 0.955 12 18
    4 Πg 90 612 6.831 12 19
    5 Πu 720 730 1.013 12 20
NH3 Ammonia 1 A1 3487 3337 0.957 13 21
    2 A1 1099 950 0.865 13 22
    3 E 3630 3444 0.949 13 23
    4 E 1662 1627 0.979 13 24
H2CO Formaldehyde 1 A1 2943 2782 0.945 14 25
    2 A1 1742 1746 1.002 14 26
    3 A1 1557 1500 0.963 14 27
    4 B1 1196 1167 0.975 14 28
    5 B2 3009 2843 0.945 14 29
    6 B2 1283 1249 0.974 14 30
BF3 Borane, trifluoro- 1 A1' 888 888 1.000 15 31
    2 A2" 695 691 0.994 15 32
    3 E' 1476 1449 0.982 15 33
    4 E' 472 480 1.016 15 34
AlF3 Aluminum trifluoride 1 A1' 671 690 1.028 16 35
    2 A2" 298 297 0.995 16 36
    3 E' 936 935 0.999 16 37
    4 E' 241 263 1.092 16 38
CH4 Methane 1 A1 3052 2917 0.956 17 39
    2 E 1558 1534 0.985 17 40
    3 T2 3179 3019 0.950 17 41
    4 T2 1370 1306 0.953 17 42
C2H6 Ethane 1 A1g 3054 2954 0.967 18 43
    2 A1g 1453 1388 0.955 18 44
    3 A1g 1014 995 0.981 18 45
    4 A1u 326 289 0.888 18 46
    5 A2u 3052 2896 0.949 18 47
    6 A2u 1428 1379 0.966 18 48
    7 Eg 3119 2969 0.952 18 49
    8 Eg 1512 1468 0.971 18 50
    9 Eg 1241 1190 0.959 18 51
    10 Eu 3141 2985 0.950 18 52
    11 Eu 1516 1469 0.969 18 53
    12 Eu 829 822 0.991 18 54
C3H6 Cyclopropane 1 A1' 3168 3038 0.959 19 55
    2 A1' 1539 1479 0.961 19 56
    3 A1' 1215 1188 0.978 19 57
    4 A1" 1187 1126 0.949 19 58
    5 A2' 1113 1070 0.962 19 59
    6 A2" 3265 3103 0.950 19 60
    7 A2" 870 854 0.982 19 61
    8 E' 3158 3025 0.958 19 62
    9 E' 1491 1438 0.964 19 63
    10 E' 1102 1029 0.934 19 64
    11 E' 889 866 0.975 19 65
    12 E" 3245 3082 0.950 19 66
    13 E" 1233 1188 0.963 19 67
    14 E" 764 739 0.967 19 68
CH2CHCH3 Propene 1 A' 3252 3090 0.950 20 69
    2 A' 3166 3013 0.952 20 70
    3 A' 3156 2991 0.948 20 71
    4 A' 3130 2954 0.944 20 72
    5 A' 3041 2871 0.944 20 73
    6 A' 1692 1650 0.975 20 74
    7 A' 1514 1470 0.971 20 75
    8 A' 1468 1420 0.967 20 76
    9 A' 1429 1378 0.964 20 77
    10 A' 1329 1297 0.976 20 78
    11 A' 1199 1171 0.977 20 79
    12 A' 952 963 1.012 20 80
    13 A' 929 920 0.990 20 81
    14 A' 423 428 1.011 20 82
    15 A" 3108 2954 0.950 20 83
    16 A" 1483 1443 0.973 20 84
    17 A" 1071 1045 0.976 20 85
    18 A" 994 991 0.997 20 86
    19 A" 825 912 1.106 20 87
    20 A" 554 578 1.044 20 88
    21 A" 190 174 0.914 20 89

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 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