Diode Laser Spectroscopy in the 9.8-μm ν14Band of Benzene: II. Self-, Air-, and Noble-Gas Broadening Coefficients

Abstract

High-resolution diode laser spectroscopy was applied to measure broadening coefficients in the 9.8-μm ν14band of benzene, C6H6. Self-broadening was investigated at 295 and 344 K for 73 lines between 1017.31 and 1045.85 cm−1with 9 ≤J″≤ 66 and 1 ≤K″≤ 66. The measured self-broadening coefficients at room temperature vary from 0.12 to 0.22 cm−1/atm (HWHM), whereas at 344 K the self-broadening coefficients are in an interval between 0.07 cm−1/atm to 0.16 cm−1/atm. The Anderson–Tsao–Curnutte (ATC) theory was used to deduce the benzene quadrupole moment and theb0parameter from mean values of the broadening coefficients at room temperature. It could be shown that the ATC theory is able to describe the quantum number dependence and the absolute values of the self-broadening coefficients with sufficient accuracy. The collision partner dependence of the broadening coefficients was measured for threeQ-branch lines in benzene mixtures with air, N2, He, Ne, Ar, Kr, and Xe. The results are compared with similar experiments with NO2and SO2absorption lines with the outcome that the qualitative change of the broadening coefficients with changing collision partner is similar for all three molecular gases. Air broadening was measured for additional five lines at both temperatures mentioned above. The experimental setup and the data treatment are described in Part I of this article (J. Mol. Spectrosc.,184,433).