CH3CN self-broadening coefficients and their temperature dependences for the Earth and Titan atmospheres

Theoretical self-broadening coefficients and associated temperature dependences for methyl cyanide lines in parallel (ΔK = 0) bands are reported for large ranges of rotational quantum numbers (0 ⩽ J ⩽ 70, K ⩽ 20) requested by spectroscopic databases. The calculations are performed by a semi-empirical method, particularly suitable for active molecules with large dipole moments, which needs only a few experimental data for model parameters fitting. Since the common power law for the temperature-dependence exponents is invalid for wide temperature ranges, two separate sets of temperature exponents are provided for Earth and Titan atmospheres applications.