Far Infrared CIA Spectra of N2-CH4 Pairs for Modeling of Titan's Atmosphere

✍ Scribed by Aleksandra Borysow; Chunmei Tang

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 488 KB
• Volume: 105
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.1993.1117

✦ Synopsis

We present a simple model which allows for the computation of the rototranslational band of the collision induced absorption spectra of (\mathrm{N}{2}-\mathrm{CH}{4}) pairs at temperatures between 70 and (300 \mathrm{~K}) and at frequencies of up to (\sim 550 \mathrm{~cm}^{-1}). The agreement with current experimental data has been obtained by adjusting the classical, multipole induced dipolar components by adding semiempirical quantum corrections. We have included a (Q_{6})-induction term, never considered before, which we believe is essential for the agreement we have obtained. With the set of temperature-independent parameters derived from fitting the experimental data, our model reproduces recent laboratory measurements within 124-300 K temperature and the (10-600 \mathrm{~cm}^{-1}) frequency range, within few percent root mean square. The method provides reliable temperature dependence of the absorption coefficient as a function of frequency at temperatures as low as (70 \mathrm{~K}), which are much lower than those at which laboratory measurements are taken. The work is of significance for modeling the infrared opacity of Titan's atmosphere. 1993 Academic Press, Inc.