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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-pVTZ
Scale factor How many Source
Molecules Vibrations
0.975 ± 0.020 22 50 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH4 Methane 1 A1 3028 2917 0.963 1 1
    2 E 1573 1534 0.975 1 2
    3 T2 3147 3019 0.959 1 3
    4 T2 1350 1306 0.967 1 4
C2H2 Acetylene 1 Σg 3504 3374 0.963 2 5
    2 Σg 1995 1974 0.990 2 6
    3 Σu 3396 3289 0.969 2 7
    4 Πg 592 612 1.033 2 8
    5 Πu 748 730 0.976 2 9
HCN Hydrogen cyanide 1 Σ 3434 3312 0.965 3 10
    2 Σ 2108 2089 0.991 3 11
    3 Π 717 712 0.993 3 12
CO2 Carbon dioxide 1 Σg 1340 1333 0.994 4 13
    2 Σu 2373 2349 0.990 4 14
    3 Πu 663 667 1.005 4 15
CO Carbon monoxide 1 Σ 2144 2170 1.012 5 16
H2 Hydrogen diatomic 1 Σg 4402 4401 1.000 6 17
CN Cyano radical 1 Σ 2110 2069 0.980 7 18
HCl Hydrogen chloride 1 Σ 2992 2991 1.000 8 19
HF Hydrogen fluoride 1 Σ 4128 4138 1.003 9 20
NH3 Ammonia 1 A1 3464 3337 0.963 10 21
    2 A1 1063 950 0.894 10 22
    3 E 3593 3444 0.958 10 23
    4 E 1673 1627 0.973 10 24
H2O2 Hydrogen peroxide 1 A 3777 3599 0.953 11 25
    2 A 1422 1402 0.986 11 26
    3 A 898 877 0.976 11 27
    4 A 376 371 0.986 11 28
    5 B 3777 3608 0.955 11 29
    6 B 1317 1266 0.961 11 30
N2 Nitrogen diatomic 1 Σg 2340 2359 1.008 12 31
H2O Water 1 A1 3811 3657 0.960 13 32
    2 A1 1646 1595 0.969 13 33
    3 B2 3920 3756 0.958 13 34
F2 Fluorine diatomic 1 Σg 916 917 1.001 14 35
Cl2 Chlorine diatomic 1 Σg 542 560 1.033 15 36
N2O Nitrous oxide 1 Σ 2268 2224 0.981 16 37
    2 Σ 1287 1285 0.998 16 38
    3 Π 593 589 0.993 16 39
C2 Carbon diatomic 1 Σg 1841 1855 1.008 17 40
P2 Phosphorus diatomic 1 Σg 768 781 1.016 18 41
BH3 boron trihydride 2 A2" 1158 1148 0.991 19 42
    3 E' 2695 2602 0.965 19 43
    4 E' 1217 1197 0.983 19 44
SiH3 Silyl radical 1 A1 2210 2136 0.966 20 45
    2 A1 766 728 0.951 20 46
    3 E 2247 2185 0.973 20 47
    4 E 935 922 0.987 20 48
SO Sulfur monoxide 1 Σ 1136 1151 1.013 21 49
    1 Σ 1078 1069 0.991 21 50
NF nitrogen fluoride 1 Σ 1131 1141 1.009 22 51

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