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Vibrational frequency scaling factors


Calculated vibrational frequencies ("theory" in table) are calculated at CCSD/cc-pVTZ-PP
Scale factor How many Source
Molecules Vibrations
0.954 ± 0.040 23 85 cccbdb
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Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
HSe Selenium monohydride 1 Σ 2472     1 1
SeO Selenium monoxide 1 Σ 972 906 0.932 2 2
HBr hydrogen bromide 1 Σ 2706 2559 0.946 3 3
LiBr Lithium Bromide 1 Σ 563 556 0.987 4 4
BrF Bromine monofluoride 1 Σ 693 662 0.955 5 5
BrCl Bromine monochloride 1 Σ 450 441 0.978 6 6
HI Hydrogen iodide 1 Σ 2359 2230 0.945 7 7
LiI Lithium Iodide 1 Σ 501 492 0.981 8 8
IO Iodine monoxide 1 Σ 661 681 1.031 9 9
IF Iodine monofluoride 1 Σ 640 604 0.944 10 10
NaI Sodium Iodide 1 Σ 258     11 11
ICl Iodine monochloride 1 Σ 398 381 0.959 12 12
H2Se Hydrogen selenide 1 A1 2493 2345 0.941 13 13
    2 A1 1081 1034 0.957 13 14
    3 B2 2512 2358 0.939 13 15
SeO2 Selenium dioxide 1 A1 1021 922 0.903 14 16
    2 A1 389 373 0.957 14 17
    3 B2 1069 966 0.903 14 18
BrCN Cyanogen bromide 1 Σ 2302 2198 0.955 15 19
    2 Σ 598 576 0.963 15 20
    3 Π 364 342 0.938 15 21
ICN Cyanogen iodide 1 Σ 2284 2188 0.958 16 22
    2 Σ 512 486 0.949 16 23
    3 Π 324 305 0.942 16 24
XeF2 Xenon difluoride 1 Σg 551 517 0.937 17 25
    2 Σu 596 560 0.940 17 26
    3 Πu 228 213 0.935 17 27
CH3I methyl iodide 1 A1 3110 2933 0.943 18 28
    2 A1 1308 1252 0.957 18 29
    3 A1 565 533 0.944 18 30
    4 E 3221 3060 0.950 18 31
    5 E 1490 1436 0.964 18 32
    6 E 909 882 0.970 18 33
CH2I2 Diiodomethane 1 A1 3161 2986 0.945 19 34
    2 A1 1439 1422 0.988 19 35
    3 A1 511 704 1.378 19 36
    4 A1 121 285 2.346 19 37
    5 A2 1082 1155 1.067 19 38
    6 B1 3242 3048 0.940 19 39
    7 B1 738 896 1.214 19 40
    8 B2 1165 1263 1.084 19 41
    9 B2 633 738 1.167 19 42
XeF4 Xenon tetrafluoride 1 A1g 594 554 0.933 20 43
    2 A2u 316 291 0.921 20 44
    3 B1g 558 524 0.940 20 45
    4 B2g 230 218 0.949 20 46
    5 B2u 181 216 1.194 20 47
    6 Eu 625 586 0.937 20 48
    7 Eu 162 161 0.993 20 49
C2H3I Vinyl iodide 1 A' 3265 3115 0.954 21 50
    2 A' 3236 3050 0.943 21 51
    3 A' 3170 2995 0.945 21 52
    4 A' 1669 1593 0.954 21 53
    5 A' 1431 1376 0.961 21 54
    6 A' 1287 1242 0.965 21 55
    7 A' 1023 992 0.969 21 56
    8 A' 568 545 0.960 21 57
    9 A' 313 309 0.986 21 58
    10 A" 999 948 0.949 21 59
    11 A" 959 910 0.949 21 60
    12 A" 560 539 0.963 21 61
IF5 pentafluoroiodine 1 A1 739 710 0.961 22 62
    2 A1 644 616 0.957 22 63
    3 A1 335 318 0.950 22 64
    4 B1 279 276 0.989 22 65
    5 B2 628 604 0.962 22 66
    6 B2 213     22 67
    7 E 685 591 0.863 22 68
    8 E 375 324 0.864 22 69
    9 E 198 189 0.956 22 70
C2H5I Ethyl iodide 1 A' 3134 2987 0.953 23 71
    2 A' 3121 2973 0.952 23 72
    3 A' 3056 2932 0.959 23 73
    4 A' 1517 1464 0.965 23 74
    5 A' 1499 1419 0.947 23 75
    6 A' 1432 1382 0.965 23 76
    7 A' 1271 1208 0.951 23 77
    8 A' 1088 1054 0.969 23 78
    9 A' 991 954 0.963 23 79
    10 A' 539 497 0.922 23 80
    11 A' 263 257 0.977 23 81
    12 A" 3190 3026 0.948 23 82
    13 A" 3146 2989 0.950 23 83
    14 A" 1509 1452 0.962 23 84
    15 A" 1280 1201 0.938 23 85
    16 A" 1015     23 86
    17 A" 757 741 0.979 23 87
    18 A" 264 258 0.979 23 88

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 60 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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