Analysis of Gas Absorption Coefficient at Various Pressures
MA Wei-guang, YIN Wang-bao, HUANG Tao, ZHAO Yan-ting, LI Chang-yong, JIA Suo-tang
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Department of Electronics & Information Technology, Shanxi University, Taiyuan 030006, China
Abstract：The absorption coefficient α(ν) of gas plays an important role in quantitative analysis of pollution gases and theoretical investigation of molecular parameter. In this paper we first analyze α(ν) theoretically and present a calculation method. Then we analyze 2ν3 band R3 manifold of pure CH4 and draw a conclusion that α(ν0) decreases and the peak absorption κ(ν0) increases with increasing the pressure. When the pressure is ＜0.03 and ＞2 atm, we can calculate α(ν0) using the Gaussian profile and Lorentzian profile respectively, and then analyze the relative error. Finally we analyze the peak absorption κ(ν0) at various pressures, then define the high-resolution area and high-sensitive area respectively when the pressure is ＜0.01 and ＞1 atm.
