Knowledge Bank

Measurements of the monochromatic transmittances of pressure-broadened, room-temperature water vapor samples at five laser frequencies of the $CO2$ laser in the $10.4\mu m$ hand will he presented. Three different buffer gases were used. They were pure nitrogen, an 80:20 mixture of nitrogen and oxygen, and a 60:40 mixture of nitrogen and oxygen. The measurements at the five laser lines imply that oxygen is a less efficient broadener than nitrogen. The ratio of the oxygen broadening coefficient to the nitrogen broadening coefficient was measured to be 0.75 based on the data at the R(20) laser line. Results of this study demonstrate that pure nitrogen should not be used as a broadener for atmospheric modeling of monochromatic transmittances in the laboratory.