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1975

Atomic, Molecular and Optical Physics

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Full-Text Articles in Physics

The Dynamics Of An Hcp Crystal With A Substitutional Defect, Pramod C. Karulkar Jun 1975

The Dynamics Of An Hcp Crystal With A Substitutional Defect, Pramod C. Karulkar

Dissertations and Theses

We examine the problem of the dynamics of a hexagonal close packed crystal with a single substitutional impurity. The effects of the mass and the force constant changes due to the introduction of the impurity atom are taken into account assuming nearest neighbor interactions under the harmonic approximation. Using Green’s function and group theoretical methods, the equations of motion for the perturbed normal modes are obtained in an exact form. The calculations are performed by allowing for very general force constant changes which can have noncentral as well as central contributions. Further, by assuming central forces, we simplify the equations …

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Theory Of Impurity-Induced Infrared Absorption In Cubic Crystals, S. S. Jaswal, J. M. Wadehra May 1975

Theory Of Impurity-Induced Infrared Absorption In Cubic Crystals, S. S. Jaswal, J. M. Wadehra

Physics and Astronomy Faculty Research Publications

A method to calculate the infrared absorption due to a very low concentration of defects in a diatomic cubic crystal is developed directly from the basic absorption equation in quantum mechanics when the impurity produces changes in mass and short-range force constants. It is shown that the absorption is due to the modes of T1u symmetry about the defect and is proportional to the square of the projection of the amplitudes of the ions in the defect space onto the transverse-optic modes at the zone center as determined by the perturbation. A procedure to calculate the amplitudes of …

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Studies Of Elastic And Inelastic Scattering Of H⁻ And D⁻ By Inert Gas Atoms, Siu-Kwong Lam Jan 1975

Studies Of Elastic And Inelastic Scattering Of H⁻ And D⁻ By Inert Gas Atoms, Siu-Kwong Lam

Dissertations, Theses, and Masters Projects

No abstract provided.

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