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Title: Classical and quantum mechanical studies of molecular vibrations for triatomic molecules

Miscellaneous ·
OSTI ID:7281233

This work comprises three different studies whose main goal is to understand vibrational dynamics of triatomic systems. In chapter two, a class of normal coordinates is investigated whose curvature is parameterized by a single variable. The eigenvalues and eigenfunctions of several independent mode models of molecular vibrations for SO[sub 2] and H[sub 2]O are compared to converged variational results. The energies of self-consistent-field and adiabatic wave functions are calculated and compared to the eigenvalues; Brueckner functions and natural models are evaluated and compared to the eigenfunctions. In chapter three, the vibrational dynamics of COC[sup +] and CCO[sup +] are examined using classical and quantum mechanics. A global Born-Oppenheimer potential energy surface is constructed for the [sup 2]A[double prime] electronic state from the ab initio points. Vibrational eigenvalues and intensities are variationally calculated for [sup 12]CO[sup 12]C[sup +], [sup 13]CO[sup 13]C[sup +] and [sup 13]CO[sup 12]C[sup +]. Tunneling splittings are also calculated for the two isotopic variants CCO[sup +] structures by numerically integrating trajectories and constructing Poincare surface of section plots. Motion on the CCO[sup +] surface is fairly chaotic at intermediate energies. Motion on the COC[sup +] surface below the isomerization barrier is regular, while motion above the barrier is chaotic which contrasts sharply with the quantum results. In chapter four, the energy flow in HeI[sub 2] is examined using classical methods. The author attempts to calculate the rate constant for unimolecular dissociation of the van der Waals (vdW) adduct by analytically constructing the separatrix for the He atom motion. The author numerically reconstructs the separatix using the zero order solutions of the vdW motion.

Research Organization:
Wisconsin Univ., Madison, WI (United States)
OSTI ID:
7281233
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English