Saturation dip measurements of pressure broadening in CH₃F

Abstract

The pressure-broadening coefficient of the U , : ~Q ( I , 1) transition of CH,F is measured in the infrared region using a high resolution saturation spectroscopic technique.T h e experiment employed a CO, laser locked to a Stark-tunable transition givinga tunability over 70 MHz at a linewidth better than 50 kHz. The corresponding coefficient is measured for non-zero molecular velocities in the optical field direction by using an acausta-optic modulator to provide a shifted laser frequency. It is found that long-range dipole-dipole interaction is responsible for the broadening.