Intramolecular dynamics. Ill. Theoretical studies of the CH overtone spectra for benzene
نویسندگان
چکیده
The CH overtone spectra for UCH= 1, 2, and 3 for an intermediate sized molecule, benzene, and the related intramolecular vibrational dynamics are treated theoretically. For this purpose, an artificial intelligence (AI) search technique is employed, using the evaluation function developed in Part II. The curvilinear local-normal mode coordinate system discussed in Part I is also used. The main features of the theoretical spectra are in reasonable accord with those of the experimental ones. Results reflecting the important role of the symmetry of molecules even in their high energy states are described.
منابع مشابه
Intramolecular dynamics. I. Curvilinear normal modes, local modes, molecular anharmonic Hamiltonian, and application to benzene
The Hamiltonian based on curvilinear normal modes and local modes (CNLM) is discussed using Wilson’s exact vibrational Hamiltonian as basis, the CNLM representation diagonalizing only the normal mode block of FG matrix in curvilinear internal coordinates. Using CNLM the kinetic and potential energy operators for benzene are given, including cubic and quartic anharmonicity in the potential energ...
متن کاملIntramolecular dynamics. II. Artificial intelligence search evaluation function and treatment of resonance centers for large systems
The role of resonance centers in obtaining large size matrices via an artificial intelligence (AI) search is discussed. The results are used to develop for an AI search an evaluation function which takes cognizance of isolated internal resonances in these many-state systems. The effect of later-accepted states on resonance centers is included. This evaluation function and one without a resonanc...
متن کاملUnimolecular processes in CH2OH below the dissociation barrier: O-H stretch overtone excitation and dissociation.
The OH-stretch overtone spectroscopy and dynamics of the hydroxymethyl radical, CH(2)OH, are reported in the region of the second and third overtones, which is above the thermochemical threshold to dissociation to H+CH(2)O (D(0)=9600 cm(-1)). The second overtone spectrum at 10 484 cm(-1) is obtained by double resonance IR-UV resonance enhanced multiphoton ionization (REMPI) spectroscopy via the...
متن کاملIntramolecular vibrational relaxation in aromatic molecules. 2: An experimental and computational study of pyrrole and triazine near the IVR threshold
The threshold region of vibrational energy redistribution (IVR) presents a great experimental and computational challenge for organic molecules with more than 10 degrees of freedom. The density of states tot is high and requires high resolution measurements over a wide range to cover all relevant timescales experimentally. Yet tot is sufficiently low that IVR quantities like the initial relaxat...
متن کاملVibrational relaxation of CH3I in the gas phase and in solution.
Transient electronic absorption measurements reveal the vibrational relaxation dynamics of CH(3)I following excitation of the C-H stretch overtone in the gas phase and in liquid solutions. The isolated molecule relaxes through two stages of intramolecular vibrational relaxation (IVR), a fast component that occurs in a few picoseconds and a slow component that takes place in about 400 ps. In con...
متن کامل