Simple Model for Fine Structure Transitions in Alkali-Metal Noble-Gas Collisions.

摘要

From ranging and tracking applications, to directed energy weapons, laser technology is very important to the military. An instrumental part of laser design and characterization depends on knowledge of transition rates between various atomic energy levels. Of specific interest, is determining the transition probabilities between the 2P3=2 and 2P1=2 energy levels of an alkali-metal noble-gas laser, which is found in a DPAL. The probabilities of transition, caused by collisions between alkali metal and noble gas atoms, have previously been calculated using a computationally intensive quantum mechanical model. This research project aims to develop a simplified, less intensive method. This is accomplished through the use of a semi-classical approach, where the colliding atoms are modeled as having a classical, straight-line trajectory. The transition probabilities are then calculated using time-dependent perturbation theory, where the coupling between states is obtained by expressing the diabatic coupling potential as a function of time. Numerical solutions to the time-dependent perturbation equations are obtained for various forms of coupling and are compared with an approximate analytic solution.