Low pressure line shape study of nitrogen-perturbed acetylene transitions in the ν1+ ν3band over a range of temperatures1

Abstract:

Six nitrogen-perturbed transitions of acetylene within the 1 + 3 absorption band have been recorded using athree-channel diode laser spectrometer. The goal being an improved understanding of both broadening and narrowing effectsof low-pressure acetylene under the influence of nitrogen gas. To this end we have examined C2H2 spectra using a hard collisionRautian profile over a range of five temperatures (213–333 K) and five pressures (5–40 Torr). From these fits we have obtained theN2-broadening and narrowing coefficients of C2H2 and examined their temperature dependence. The experimentally measurednarrowing coefficients have been used to estimate the nitrogen diffusion coefficients (D12) and are presented within. Thebroadening coefficients and corresponding temperature dependence exponents have also been compared to that of calculationscompleted using a classical impact approach on an ab initio potential energy surface. We have observed good agreementbetween our theoretical and experimental results.

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