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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)/aug-cc-pVDZ
Scale factor How many Source
Molecules Vibrations
0.982 ± 0.029 23 65 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH4 Methane 1 A1 3017 2917 0.967 1 1
    2 E 1535 1534 0.999 1 2
    3 T2 3144 3019 0.960 1 3
    4 T2 1319 1306 0.990 1 4
C2H2 Acetylene 1 Σg 3478 3374 0.970 2 5
    2 Σg 1970 1974 1.002 2 6
    3 Σu 3384 3289 0.972 2 7
    4 Πg 368 612 1.663 2 8
    5 Πu 692 730 1.056 2 9
HCN Hydrogen cyanide 1 Σ 3416 3312 0.969 3 10
    2 Σ 2078 2089 1.005 3 11
    3 Π 692 712 1.028 3 12
CO2 Carbon dioxide 1 Σg 1316 1333 1.013 4 13
    2 Σu 2338 2349 1.005 4 14
    3 Πu 659 667 1.012 4 15
CO Carbon monoxide 1 Σ 2104 2170 1.031 5 16
H2 Hydrogen diatomic 1 Σg 4344 4401 1.013 6 17
CN Cyano radical 1 Σ 2077 2069 0.996 7 18
HCl Hydrogen chloride 1 Σ 2969 2991 1.008 8 19
HF Hydrogen fluoride 1 Σ 4084 4138 1.013 9 20
NH3 Ammonia 1 A1 3434 3337 0.972 10 21
    2 A1 1071 950 0.887 10 22
    3 E 3571 3444 0.964 10 23
    4 E 1651 1627 0.986 10 24
H2O2 Hydrogen peroxide 1 A 3753 3599 0.959 11 25
    2 A 1409 1402 0.995 11 26
    3 A 842 877 1.042 11 27
    4 A 385 371 0.964 11 28
    5 B 3754 3608 0.961 11 29
    6 B 1301 1266 0.973 11 30
N2 Nitrogen diatomic 1 Σg 2319 2359 1.017 12 31
H2O Water 1 A1 3787 3657 0.966 13 32
    2 A1 1638 1595 0.973 13 33
    3 B2 3905 3756 0.962 13 34
F2 Fluorine diatomic 1 Σg 825 917 1.111 14 35
Cl2 Chlorine diatomic 1 Σg 502 560 1.114 15 36
N2O Nitrous oxide 1 Σ 2242 2224 0.992 16 37
    2 Σ 1277 1285 1.006 16 38
    3 Π 567 589 1.039 16 39
C2 Carbon diatomic 1 Σg 1814 1855 1.023 17 40
P2 Phosphorus diatomic 1 Σg 747 781 1.045 18 41
Si2 Silicon diatomic 1 Σg 525 511 0.974 19 42
BH3 boron trihydride 2 A2" 1146 1148 1.001 20 43
    3 E' 2676 2602 0.972 20 44
    4 E' 1203 1197 0.995 20 45
SO Sulfur monoxide 1 Σ 1071 1151 1.074 21 46
    1 Σ 1006 1069 1.062 21 47
NF nitrogen fluoride 1 Σ 1080 1141 1.056 22 48
B2H6 Diborane 1 Ag 2604 2524 0.969 23 49
    2 Ag 2160 2104 0.974 23 50
    3 Ag 1190 1180 0.991 23 51
    4 Ag 801 794 0.991 23 52
    5 Au 833 833 1.000 23 53
    6 B1g 2680 2591 0.967 23 54
    7 B1g 923 915 0.991 23 55
    8 B1u 1979 1915 0.968 23 56
    9 B1u 982 973 0.991 23 57
    10 B2g 1873 1768 0.944 23 58
    11 B2g 876 850 0.970 23 59
    12 B2u 2697 2612 0.969 23 60
    13 B2u 962 950 0.988 23 61
    14 B2u 366 368 1.006 23 62
    15 B3g 1051 1012 0.963 23 63
    16 B3u 2588 2525 0.976 23 64
    17 B3u 1741 1602 0.920 23 65
    18 B3u 1174 1177 1.002 23 66

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.

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