Infrared spectroscopy and modeling of co-crystalline CO 2· C 2H 2 aerosol particles. I. the formation and decomposition of co-crystalline CO 2·C 2H 2 aerosol particles

Abstract

Aerosol particles composed of co-crystalline CO 2C 2H 2 were generated in a bath gas cooling cell at cryogenic temperatures and investigated with infrared spectroscopy between 600 and 4000 cm -1. Similar to results obtained for thin films of the co-crystal T. E. Gough and T. E. Rowat, J. Chem. Phys. 109, 6809 (1998), this phase was found to be metastable and decomposed into pure CO 2 and pure C 2H 2. These decomposed aerosols were characterized through (i) a comparison to experimentally prepared aerosols of mixed CO 2 and C 2H 2 of known architectures and (ii) the modeling of infrared spectra. A likely architecture after decomposition are C 2H 2-CO 2 core-shell particles with a disk-like shape. The co-crystalline CO 2·C 2H 2 aerosols prior to decomposition are modeled and analyzed in detail in the subsequent paper (Part II). © 2012 American Institute of Physics.