C-H and C-D interbond coupling in CHD₂Cl

Ring Puckering and CH Stretching Spectra. 2. High Vibrational States of Gaseous Monohydrogenated Cyclopentene-3-h1

“…Fermi resonances between CH bond stretching and bending modes are very common in the high vibrational states of organic molecules.5-20 Whereas the existence of such Fermi resonances has been known for a long time,51-52 only much more recently has this been analyzed systematically and recognized as one of the major pathways of intramolecular energy flow in organic molecules. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] In particular, Quack and co-workers have thoroughly studied the high vibrational states of CHX3 molecules and compared effective Hamiltonians formulated in different coordinates (rectilinear or curvilinear, internal or normal) with ab initio calculations. For the molecules they studied, the best choice was a treatment based on rectilinear normal coordinates using a polar coordinate representation of the potential.11 The most serious limitations of the curvilinear internal coordinates models seemed to be the neglect of coupling to the motions of the heavy atom CX3 frame which is important in the case of relatively small molecules like CHX3.…”

Vibrational overtone spectroscopy and internal dynamics in gaseous nitromethane NO2CH2D

“…Isotopic substitution is a useful tool to determine some of the mechanisms by which vibrational deactivation of large molecules occurs. 7,18,[20][21][22] However, several molecular properties could be changed with the degree and location of the deuteration, in particular symmetry and equilibrium conformation as shown in nitromethane. 23 An analysis combining observations of different isotopomers is thus necessary to obtain sufficient information to disentangling the complex and various ways of the energy flow and to model the IVR phenomena.…”

The General Harmonic Force Field of Methyl Chloride

“…Anharmonicity factors for the other isotopic species were calculated in this work using Dennison's relaxation x* i ϭ x i * i / i . Direct calculation of 1 -1 for 12 CHD 2 Cl from a near complete set of x ij for this vibrational mode (14,15) gives a correction of Ϫ147 cm Ϫ1 compared with Ϫ141 cm Ϫ1 using Dennison's relation. This observation reenforces our confidence that the anharmonic corrections applied here are radically better that those used in earlier studies of the harmonic force field of methyl chloride.…”