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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)/6-31+G**
Scale factor How many Source
Molecules Vibrations
0.960 ± 0.026 33 68 cccbdb
Jump to histogram
Formula Name Mode Symmetry Frequency Count
Theory Experiment ratio molecules vibrations
CH4 Methane 1 A1 3083 2917 0.946 1 1
    2 E 1585 1534 0.968 1 2
    3 T2 3212 3019 0.940 1 3
    4 T2 1389 1306 0.941 1 4
NaOH sodium hydroxide 1 Σ 3992 3637 0.911 2 5
    2 Σ 549 540 0.984 2 6
    3 Π 320 300 0.937 2 7
H2 Hydrogen diatomic 1 Σg 4505 4401 0.977 3 8
CS carbon monosulfide 1 Σ 1281 1285 1.003 4 9
CH Methylidyne 1 Σ 2875 2861 0.995 5 10
OH Hydroxyl radical 1 Σ 3747 3738 0.997 6 11
LiH Lithium Hydride 1 Σ 1375 1405 1.022 7 12
NaH sodium hydride 1 Σ 1138 1172 1.030 8 13
HCl Hydrogen chloride 1 Σ 3048 2991 0.981 9 14
HF Hydrogen fluoride 1 Σ 4127 4138 1.003 10 15
NH3 Ammonia 1 A1 3525 3337 0.947 11 16
    2 A1 1075 950 0.884 11 17
    3 E 3679 3444 0.936 11 18
    4 E 1705 1627 0.954 11 19
MgH2 magnesium dihydride 2 Σu 1617 1572 0.972 12 20
    3 Πu 446 440 0.986 12 21
H2O Water 1 A1 3856 3657 0.949 13 22
    2 A1 1640 1595 0.973 13 23
    3 B2 3987 3756 0.942 13 24
H2S Hydrogen sulfide 1 A1 2766 2615 0.945 14 25
    2 A1 1256 1183 0.942 14 26
    3 B2 2790 2626 0.941 14 27
AlH3 aluminum trihydride 1 A1' 1966 1900 0.967 15 28
    2 A2" 724 698 0.963 15 29
    3 E' 1979 1883 0.951 15 30
    4 E' 812 783 0.964 15 31
BeH2 beryllium dihydride 2 Σu 2291 2159 0.943 16 32
    3 Πu 716 698 0.975 16 33
PH3 Phosphine 1 A1 2459 2323 0.945 17 34
    2 A1 1061 992 0.935 17 35
    3 E 2473 2328 0.941 17 36
    4 E 1153 1118 0.969 17 37
SiH4 Silane 1 A1 2299 2187 0.951 18 38
    2 E 997 975 0.978 18 39
    3 T2 2310 2191 0.949 18 40
    4 T2 956 914 0.956 18 41
BH3 boron trihydride 2 A2" 1189 1148 0.965 19 42
    3 E' 2763 2602 0.942 19 43
    4 E' 1250 1197 0.958 19 44
BeH beryllium monohydride 1 Σ 2092 2061 0.985 20 45
PH2 Phosphino radical 1 A1 2425 2310 0.953 21 46
    2 A1 1160 1102 0.950 21 47
SiH3 Silyl radical 1 A1 2268 2136 0.942 22 48
    2 A1 799 728 0.911 22 49
    3 E 2305 2185 0.948 22 50
    4 E 964 922 0.956 22 51
BH Boron monohydride 1 Σ 2411 2367 0.981 23 52
NH2 Amino radical 1 A1 3397 3219 0.948 24 53
    2 A1 1551 1497 0.965 24 54
    3 B2 3509 3301 0.941 24 55
NH Imidogen 1 Σ 3289 3283 0.998 25 56
SiH Silylidyne 1 Σ 2071 2043 0.986 26 57
SiH2 silicon dihydride 1 A1 2107 1996 0.947 27 58
    2 A1 1046 999 0.955 27 59
    3 B2 2110 1993 0.944 27 60
SH Mercapto radical 1 Σ 2728 2696 0.988 28 61
PH phosphorus monohydride 1 Σ 2383 2364 0.992 29 62
AlH aluminum monohydride 1 Σ 1713 1682 0.982 30 63
MgH magnesium monohydride 1 Σ 1469 1493 1.016 31 64
BH2 boron dihydride 2 A1 1060 954 0.899 32 65
AlH2 aluminum dihydride 1 A1 1875 1770 0.944 33 66
    2 A1 788 760 0.964 33 67
    3 B2 1915 1807 0.943 33 68

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