Coherent enantiomeric control and controlled intramolecular vibrational redistribution.
Contributors: University of Toronto.  Dept. of Chemistry.
Published: 2005
Language: eng
Number of pages: 160
Description: Extensive control over enantiomer populations using achiral light is computationally demonstrated using a model of 1,3 dimethylallene. In particular, chiral purification of a racemic mixture using the dipole-electric field interaction is examined in detail for two different scenarios. First is our "laser distillation" scheme, where it is shown that chiral control in an randomly oriented racemic mixture is possible using three mutually perpendicular linearly polarized light fields. Furthermore, elastic and inelastic collisions and internal conversion are included, rendering realism to the system but also serving to reduce the effects of quantum interference and, consequently, to reduce the degree of control. Nonetheless, population enhancement of a desired enantiomer is possible by varying system parameters, such as pulse durations, field strengths etc. Second is a proposed two step optical control scenario. In the first step, three laser pulses of mutually perpendicular linear polarizations, applied in a "cyclic adiabatic passage" scheme, are shown to be able to distinguish between the L and D enantiomers due to their difference in matter-radiation phase. In the second step, which immediately follows the first, a sequence of pulses is used to convert one enantiomer to its mirror-image form. This scenario, which only negligibly populates the first excited electronic state, proves extremely useful for systems such as dimethylallene, which can suffer losses from dissociation and internal conversion upon electronic excitation.Next, the suppression and enhancement of decay is considered. Specifically, we utilize the interference between overlapping resonances to alter the radiationless processes of internal conversion (IC) and of intramolecular vibrational redistribution (IVR). Here the theory of both bound-continuum and bound-bound processes are treated in detail with examples of both cases presented for the molecules 1,3 dimethylallene and OCS.
Notes: Advisor: Paul Brumer

Thesis (Ph.D.)--University of Toronto, 2005.

Electronic version licensed for access by U. of T. users.

Source: Dissertation Abstracts International, Volume: 66-06, Section: B, page: 3147.