Abstract

A previous study on the absorption spectrum of C₃F₇I indicated the presence of a transition of the collisionless absorption spectrum in the presence of collisions.¹ We report a systematic study of the pressure dependence of this spectrum to investigate the characteristics of this transition. C₃F₇I, with 27 vibrational degrees of freedom, has a room-temperature spectrum that is congested with multitudes of hot bands owing to low-frequency modes. The molecule is, therefore, in its quasicontinuum (QC) of vibrational states at room temperature. The consequent IR spectrum is smooth and featureless. Tire C-F stretch absorption spectrum, spanning 1020-1060 cm⁻¹, is used in this experiment because it overlaps the 9-μm CO₂ laser transitions.

© 1991 Optical Society of America