Sensitive measurement of adsorption dynamics with nonresonant gas phase photoacoustics

Abstract

A nonresonant photoacoustic cell, excited by 10-micros CO(2) laser pulses, is compared with conventional resonant cells excited with modulated cw radiation. By combining high sensitivity with small volume and small surface area, the nonresonant cell shows superior performance in measurements of time-dependent concentrations. The potential of the cell is illustrated by measurements of the time evolution of adsorption and desorption of ammonia molecules from surfaces of quartz and stainless steel.