CO2 Laser Absorption Measurement of CH3CH2Br using Photoacoustic Method

Abstract

The CO2 laser absorption measurement of CH3CH2Br utilizing photoacoustic (PA) technique was performed using a cw and a pulsed CO2 lasers. The absorption profile in the CO2 laser wavelength region (9-10 mum) and the macroscopic small signal absorption cross section at 10P(20) (10.59 mum, 944 cm-1) laser line were measured using a cw CO2 laser. The laser fluence dependence on infrared multiphoton absorption (IRMPA) was also studied with a pulsed TEA CO2 laser at 10P(20) laser line. In view of monotonic increase of PA signal with the rise of laser fluence, it was suggested that the anharmonicity in pumped vibration mode did not restrict ir multiphoton absorption in CH3CH2Br system as found in large molecular system.