On the velocity distribution of molecular species in pulsed optical lattices

Coherent Rayleigh scattering was, for the first time, simulated using the Direct Simulation Monte-Carlo technique with the motivation of ultimately using experimental line shapes to directly measurement the velocity distribution of the gas. Carbon dioxide, at 300 K and low pressure, was simulated at various laser energies in the collisionless regime and at various pressures for a simulated laser intensity of 4×1015 W/m2. Simulated results compare favorably to published experimental results and existing kinetic line shape models, appropriately capturing line shape narrowing with increased optical potential well depth. Additionally, the expected line shape from a non-equilibrium gas with a bi-Gaussian velocity distribution was investigated. As with an equilibrium gas, the simulated line shape follows the velocity distribution and exhibits line narrowing with increasing laser intensity.