Vibrational dependence of line coupling and line mixing in self-broadened parallel bands of NH 3

摘要

AbstractLine coupling and line mixing effects have been calculated for several self-broadened NH3lines in parallel bands involving an excited ν2mode. It is well known that once the ν2mode is excited, the inversion splitting quickly increases as this quantum number increases. In the present study, we have shown that the ν2dependence of the inversion splitting plays a dominant role in the calculated line-shape parameters. For the ν2band with a 36cm?1splitting, the intra-doublet couplings practically disappear and for the 2ν2and 2ν2- ν2bands with much higher splitting values, they are completely absent. With respect to the inter-doublet coupling, it becomes the most efficient coupling mechanism for the ν2band, but it is also completely absent for bands with higher ν2quantum numbers. Because line mixing is caused by line coupling, the above conclusions on line coupling are also applicable for line mixing. Concerning the check of our calculated line mixing effects, while the present formalism has well explained the line mixing signatures observed in the ν1band, there are large discrepancies between the measured Rosenkranz mixing parameters and our calculated results for the ν2and 2ν2bands. In order to clarify these discrepancies, we propose to make some new measurements. In addition, we have calc