![Sample our Engineering & Technology journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5933/TOC-Subject-Sample-2021-Engineering-Tech.jpg"})
Abstract
A new technique for measuring the dynamic friction coefficient η in a gas sample at low pressure is described. By varying the distance between two spatially separate antiparallel laser beams in a saturable absorber, we are able to follow the dynamics of the Bennett hole and resonant spike, caused by non-linear absorption, in the molecular velocity distribution. Iodine in the presence of 1 torr of argon buffer gas is studied using an Ar+ laser, and η is found to be approximately 2000 s-1, corresponding to a 10-3 fractional change in velocity in one collision. The technique is capable in principle of measuring diffusion coefficients and fluorescence lifetimes, and it involves information on both the ground and excited states.
Supported by the National Science Foundation.
Supported by the National Science Foundation.
Notes
Supported by the National Science Foundation.