Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.812572
Title: Rotation-vibration states of triatomic molecules using massively parallel computers
Author: Mussa, Hamse Yussuf
Awarding Body: University of London
Current Institution: University College London (University of London)
Date of Award: 1999
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Abstract:
A formulation of the the nuclear motion (rotation-vibration) of triatomic molecules is discussed in the different implementations of the Discrete Variable Representation (DVR). The formulation is expressed in a set of internal co-ordinates using an exact nuclear motion Hamiltonian operator. We present a computer implementation of the Hamiltonian on some of the most powerful massively parallel computers in the world today. The Cray-T3E/T3D, and the IBM SP2 are used for this study. Accurate calculations of the rotation-vibrational energy levels up to the dissociation for the non-linear triatomic molecules, H2O and O3, with deep potential surfaces are presented. We also present results for two linear molecules, HN+2 and HCP. The water molecule is used as a detailed case study. Rotation-vibration studies are made using a number of realistic global potential energy surfaces. Radau co-ordinates are used for the calculations in the preconditioned DVR representation. After comprehensive variational convergence tests on the energy levels, all the J=0 bound states of the system are converged to within l cm-1 or better, giving about 1,000 states for each potential. Graphical analyses of the eigenfunctions are then made. Similar studies are performed for the J > 0. These are the first accurate rotation-vibrational calculations up to the dissociation obtained for this system. For the J > 0 case, convegence problems are found in previous, more limited, studies of the system.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.812572  DOI: Not available
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