The HCl + ClONO_2 reaction rate on various water ice surfaces

摘要

The reaction ClONO_2 + HCl -> Cl_2 + HNO_3 on ice surfaces was investigated using a fast flow reactor coupled to a chemical ionization mass spectrometer. Rough and relatively smooth ice surfaces and single-crystal ice particles were employed to investigate the effect of the different surface morphologies on the reaction mechanism. Large reaction probabilities (#gamma#>0.1), independent of HCl partial pressure in the range from 2 * 10~(-7) to 8 * 10~(-6) Torr, were measured on these three ice surfaces. These results are consistent with an ionic reaction mechanism involving HCl solvation on a liquid-like surface layer.