An investigation of polarized atomic photofragments using the ion imaging technique

This thesis describes measurement and analysis of the recoil angle dependence of atomic photofragment polarization (atomic v-J correlation). This property provides information on the electronic rearrangement which occurs during molecular photodissociation. Chapter 1 introduces concepts of photofragment vector correlations and reviews experimental and theoretical progress in this area. Chapter 2 described the photofragment ion imaging technique, which the author has used to study the atomic v-J correlation in chlorine and ozone dissociation. Chapter 3 outlines a method for isolating and describing the contribution to the image signal which is due exclusively to angular momentum alignment. Ion imaging results are presented and discussed in Chapter 4. Chapter 5 discusses a different set of experiments on the three-fragment dissociation of azomethane. 122 refs

Positively and negatively charged magneto excitons in GaAs/Ga 1- x Al x As double quantum wells

Binding energies of positively and negatively charged magneto excitons are investigated by using the variational procedure within the single band effective mass approximation. A linear Rashba spin-orbit coupling module with the position dependent electron is included in our calculations in order to study the change in spin-orbit splitting energy. In continuation, the interband optical transition, with and without the exciton, is computed as a function of well width. The valence-band anisotropy is included in our theoretical model by using different hole masses in different spatial directions. It is observed that (i) negative trions are found to have a higher binding energy than positive trions, (ii) the exciton binding energy and the interband emission energy both increase when the well width is decreased and (iii) the effect of exciton has influence on the interband emission energy. The results of the present investigation are found to be in good agreement with the recently published results. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2010