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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)/cc-pVTZ
Scale factor How many Source
Molecules Vibrations
0.975 ± 0.021 30 61 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH4 Methane 1 A1 3036 2917 0.961 1 1
    2 E 1570 1534 0.977 1 2
    3 T2 3155 3019 0.957 1 3
    4 T2 1343 1306 0.972 1 4
H2 Hydrogen diatomic 1 Σg 4411 4401 0.998 2 5
CS carbon monosulfide 1 Σ 1269 1285 1.012 3 6
CH Methylidyne 1 Σ 2835 2861 1.009 4 7
    1 Σ 3109 3145 1.011 4 8
OH Hydroxyl radical 1 Σ 3740 3738 0.999 5 9
CCl carbon monochloride 1 Σ 866 877 1.012 6 10
HCl Hydrogen chloride 1 Σ 3001 2991 0.997 7 11
HF Hydrogen fluoride 1 Σ 4181 4138 0.990 8 12
NH3 Ammonia 1 A1 3471 3337 0.961 9 13
    2 A1 1112 950 0.854 9 14
    3 E 3596 3444 0.958 9 15
    4 E 1688 1627 0.964 9 16
H2O Water 1 A1 3841 3657 0.952 10 17
    2 A1 1668 1595 0.956 10 18
    3 B2 3945 3756 0.952 10 19
F2 Fluorine diatomic 1 Σg 920 917 0.997 11 20
H2S Hydrogen sulfide 1 A1 2717 2615 0.962 12 21
    2 A1 1204 1183 0.982 12 22
    3 B2 2733 2626 0.961 12 23
AlH3 aluminum trihydride 1 A1' 1940 1900 0.979 13 24
    2 A2" 718 698 0.972 13 25
    3 E' 1946 1883 0.967 13 26
    4 E' 792 783 0.990 13 27
PH3 Phosphine 1 A1 2412 2323 0.963 14 28
    2 A1 1018 992 0.974 14 29
    3 E 2421 2328 0.962 14 30
    4 E 1142 1118 0.979 14 31
SiH4 Silane 1 A1 2251 2187 0.972 15 32
    2 E 984 975 0.991 15 33
    3 T2 2258 2191 0.970 15 34
    4 T2 931 914 0.982 15 35
C2 Carbon diatomic 1 Σg 1846 1855 1.005 16 36
Si2 Silicon diatomic 1 Σg 543 511 0.942 17 37
BH3 boron trihydride 2 A2" 1160 1148 0.989 18 38
    3 E' 2698 2602 0.964 18 39
    4 E' 1223 1197 0.979 18 40
PH2 Phosphino radical 1 A1 2386 2310 0.968 19 41
    2 A1 1125 1102 0.980 19 42
SiH3 Silyl radical 1 A1 2219 2136 0.963 20 43
    2 A1 775 728 0.939 20 44
    3 E 2255 2185 0.969 20 45
    4 E 941 922 0.980 20 46
BH Boron monohydride 1 Σ 2351 2367 1.007 21 47
NH2 Amino radical 1 A1 3365 3219 0.957 22 48
    2 A1 1558 1497 0.961 22 49
    3 B2 3457 3301 0.955 22 50
NH Imidogen 1 Σ 3266 3283 1.005 23 51
    1 Σ 3323 3314 0.997 23 52
SiH Silylidyne 1 Σ 2032 2043 1.005 24 53
SiH2 silicon dihydride 1 A1 2064 1996 0.967 25 54
    2 A1 1023 999 0.977 25 55
    3 B2 2063 1993 0.966 25 56
SH Mercapto radical 1 Σ 2687 2696 1.003 26 57
PH phosphorus monohydride 1 Σ 2352 2364 1.005 27 58
    1 Σ 2373 2415 1.018 27 59
AlH aluminum monohydride 1 Σ 1681 1682 1.001 28 60
BH2 boron dihydride 2 A1 1018 954 0.937 29 61
AlH2 aluminum dihydride 1 A1 1847 1770 0.958 30 62
    2 A1 766 760 0.993 30 63
    3 B2 1883 1807 0.959 30 64

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.

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