
Accession Number : ADA116253
Title : Quantum Dynamical Model of LaserStimulated Isotope Separation of Adsorbed Species: Role of Anharmonicity, Coupling Strength and Energy Feedback from the Heated Substrate.
Descriptive Note : Technical rept.,
Corporate Author : ROCHESTER UNIV NY DEPT OF CHEMISTRY
Personal Author(s) : Lin,JuiTeng ; George,Thomas F
PDF Url : ADA116253
Report Date : Jun 1982
Pagination or Media Count : 63
Abstract : A quantum model of a heterogeneous system consisting of a mixture of isotopes adsorbed on a solid surface and subjected to laser radiation is presented. The model system is described by a total Hamiltonian including direct and indirect (surfacephononmediated) couplings. The equations of motion are derived in the HeisenbergMarkoffian picture in which the manybody effects of the surface phonon modes and the adspecies are reduced to an overall broadening (damping factor) given by the sum of the energy (T1) and phase (T2) relaxations. The effects of the dephasing and anharmonicity on the average excitation are investigated. The 'bistability' feature with a redshifted optimal detuning is discussed in terms of the solution of a cubic equation. A diagonalization procedure is presented in a new basis which reveals the effects of the coupling strength, the frequency difference and the level width of the isotopes on the total steadystate excitation, which in turn reflects the surface spectrum of the model system. Finally, the isotope selectivity given by the numerical results of the timeintegrated excitations is discussed. It is shown that the optimal detuning for a weak coupling strength is further redshifted for a strong isotopic coupling strength. Finally, energy feedback effects of the bath modes on the excitations of the active modes are investigated by combining a quantum excitation equation and a classical heat diffusion equation. (Author)
Descriptors : *Isotope separation, *Radiation absorption, *Laser beams, *Quantum theory, *Coupling(Interaction), Energy transfer, Dynamics, Strength(General), Thermal diffusion, Excitation, Relaxation, Steady state, Heterogeneity, Substrates, Damping, Equations of motion, Mathematical models, Time dependence, Heat treatment, Feedback
Subject Categories : Quantum Theory and Relativity
Distribution Statement : APPROVED FOR PUBLIC RELEASE