Large Amplitude Quantum Mechanics in Polyatomic Hydrides:I. A Particles-on-a-Sphere Model for XH^dn.

Published

August 1, 2005

Author(s)

M Deskevich, David Nesbitt

Abstract

A framework is presented for converged quantum mechanical calculations on large amplitude dynamics in polyatomic hydrides (XH_{n), based on a relatively simple but computationally tractable particles-on-a-sphere (POS) model for the intramolecular motion of the light atoms. The modle assumes independent 2D angular motion of H atoms imbedded on the surface of a sphere with an arbitrary interatomic angular potential, which permits systematic evolution from free rotor to funneling to quasi'rigid polyatomic molecule behavior for small but finite values of total angular momentum J. This work focuses on simple triatom (n=2) and tetratom (n=3) systems as a function of interatomic potential stiffness, with explicit consideration of H}d2^o, NH_{3, and H}d3O^+ as limiting test cases. The particles on a sphere model also establishes the necessary mathematical groundwork for calculations on dynamically much more challenging XH_{2, species with n greater than 3, (e.g., models of CH}d5^+), where such a reduced dimensionally approach offers prospects for being both quantitatively reliable and yet quantum mechanically tractable, at least for low J values (i.e.,J =0,1,2) characateristic of supersonic jet expansion conditions.

Citation

Journal of Chemical Physics

Volume

123

Pub Type

Journals

Keywords

hydrides, large amplitude motion, multidimensional quantum mechanics, rovibrational spectroscopy

Citation

Deskevich, M. and Nesbitt, D. (2005), Large Amplitude Quantum Mechanics in Polyatomic Hydrides:I. A Particles-on-a-Sphere Model for XH^dn., Journal of Chemical Physics (Accessed July 17, 2024)