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III.B.3.b. (XIII.C.2.)

Vibrational frequency scaling factors

Calculated vibrational frequencies ("theory" in table) are calculated at CCSD(T)=FULL/6-31G*
Scale factor How many Source
Molecules Vibrations
0.971 ± 0.031 30 95 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
H2CO Formaldehyde 1 A1 2956 2782 0.941 1 1
    2 A1 1795 1746 0.973 1 2
    3 A1 1566 1500 0.958 1 3
    4 B1 1185 1167 0.985 1 4
    5 B2 3021 2843 0.941 1 5
    6 B2 1285 1249 0.972 1 6
HCOOH Formic acid 1 A' 3661 3570 0.975 2 7
    2 A' 3113 2943 0.945 2 8
    3 A' 1846 1770 0.959 2 9
    4 A' 1432 1387 0.968 2 10
    5 A' 1344 1229 0.915 2 11
    6 A' 1153 1105 0.958 2 12
    7 A' 626 625 0.998 2 13
    8 A" 1054 1033 0.980 2 14
    9 A" 701 638 0.911 2 15
CH4 Methane 1 A1 3056 2917 0.954 3 16
    2 E 1598 1534 0.960 3 17
    3 T2 3178 3019 0.950 3 18
    4 T2 1395 1306 0.936 3 19
C2H6 Ethane 1 A1g 3055 2896 0.948 4 20
    2 A1g 1476 1388 0.940 4 21
    3 A1g 1034 995 0.962 4 22
    4 A1u 322 289 0.898 4 23
    5 A2u 3054 2915 0.955 4 24
    6 A2u 1449 1370 0.946 4 25
    7 Eg 3116 2969 0.953 4 26
    8 Eg 1546 1468 0.950 4 27
    9 Eg 1256 1190 0.948 4 28
    10 Eu 3138 2974 0.948 4 29
    11 Eu 1551 1460 0.941 4 30
    12 Eu 839 822 0.980 4 31
C2H2 Acetylene 1 Σg 3520 3374 0.959 5 32
    2 Σg 2024 1974 0.976 5 33
    3 Σu 3425 3289 0.960 5 34
    4 Πg 358 612 1.708 5 35
    5 Πu 735 730 0.993 5 36
HCN Hydrogen cyanide 1 Σ 3466 3312 0.955 6 37
    2 Σ 2130 2089 0.981 6 38
    3 Π 714 712 0.998 6 39
CS2 Carbon disulfide 1 Σg 673 658 0.977 7 40
    2 Σu 1571 1535 0.977 7 41
    3 Πu 397 397 1.000 7 42
CO2 Carbon dioxide 1 Σg 1349 1333 0.989 8 43
    2 Σu 2417 2349 0.972 8 44
    3 Πu 645 667 1.035 8 45
ClCN chlorocyanogen 1 Σ 2264 2216 0.979 9 46
    2 Σ 741 744 1.004 9 47
    3 Π 355 378 1.065 9 48
CO Carbon monoxide 1 Σ 2159 2170 1.005 10 49
H2CS Thioformaldehyde 1 A1 3111 2971 0.955 11 50
    2 A1 1544 1456 0.943 11 51
    3 A1 1071 1059 0.989 11 52
    4 B1 1009 990 0.981 11 53
    5 B2 3200 3025 0.945 11 54
    6 B2 1036 991 0.957 11 55
MgO magnesium oxide 1 Σ 747 785 1.051 12 56
CN Cyano radical 1 Σ 2120 2069 0.976 13 57
CH Methylidyne 1 Σ 3174 3145 0.991 14 58
OH Hydroxyl radical 1 Σ 3630 3738 1.030 15 59
CF Fluoromethylidyne 1 Σ 1310 1308 0.999 16 60
SO2 Sulfur dioxide 1 A1 1111 1151 1.036 17 61
    2 A1 499 518 1.038 17 62
    3 B2 1324 1362 1.028 17 63
LiH Lithium Hydride 1 Σ 1332 1405 1.055 18 64
BF3 Borane, trifluoro- 1 A1' 892 888 0.995 19 65
    2 A2" 701 691 0.985 19 66
    3 E' 1505 1449 0.963 19 67
    4 E' 483 480 0.994 19 68
HCl Hydrogen chloride 1 Σ 2962 2991 1.010 20 69
HF Hydrogen fluoride 1 Σ 4006 4138 1.033 21 70
NH3 Ammonia 1 A1 3435 3337 0.972 22 71
    2 A1 1180 950 0.805 22 72
    3 E 3576 3444 0.963 22 73
    4 E 1747 1627 0.932 22 74
MgH2 magnesium dihydride 2 Σu 1583 1572 0.993 23 75
    3 Πu 442 440 0.996 23 76
H2O2 Hydrogen peroxide 1 A 3698 3599 0.973 24 77
    2 A 1455 1402 0.964 24 78
    3 A 879 877 0.998 24 79
    4 A 326 371 1.137 24 80
    5 B 3701 3608 0.975 24 81
    6 B 1311 1266 0.965 24 82
N2 Nitrogen diatomic 1 Σg 2345 2359 1.006 25 83
H2O Water 1 A1 3726 3657 0.981 26 84
    2 A1 1742 1595 0.916 26 85
    3 B2 3856 3756 0.974 26 86
F2 Fluorine diatomic 1 Σg 890 917 1.031 27 87
Cl2 Chlorine diatomic 1 Σg 503 560 1.112 28 88
H2S Hydrogen sulfide 1 A1 2702 2615 0.968 29 89
    2 A1 1257 1183 0.941 29 90
    3 B2 2726 2626 0.963 29 91
AlH3 aluminum trihydride 1 A1' 1924 1900 0.988 30 92
    2 A2" 702 698 0.994 30 93
    3 E' 1942 1883 0.970 30 94
    4 E' 786 783 0.997 30 95

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.

45
40
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