Extended calculations of nitrogen-induced line broadening coefficients in the ν7 band of ethylene

Abstract

Computations of room-temperature N${}_2$-broadening coefficients are performed for 3546 lines in the ${\nu }_7$ infrared absorption band of ethylene to provide data required for atmospheric studies but missing in spectroscopic databases. The calculations are done in the framework of a semi-classical exact-trajectory approach developed previously (Buldyreva and Nguyen, 2008). The active molecule is rigorously treated as an asymmetric top and the perturber is traditionally considered to be in its ground vibrational state. The data are provided for the ${}^{\mathrm{P,R}}$P-, ${}^{\mathrm{P,R}}$Q- and ${}^{\mathrm{P,R}}$R-subbranches (lines with $\Delta K_a=\pm 1$ having observable intensities) for (initial) rotational quantum numbers $J$ up to 22, limited by the available numerical energies for the excited vibrational level. Moreover, potentially detectable lines with $\Delta K_a=\pm 3$ are also considered for $J\le 13$, limited by high computational cost. Being validated by comparison with existing experimental results, these data can replace unavailable measurements and will be useful for atmospheric/industrial applications.