Photodissociation of methyl iodide adsorbed on low-temperature amorphous ice surfaces
作者： Alice J. DeSimone , Babajide O. Olanrewaju , Gregory A. Grieves , Thomas M. Orlando
DOI: 10.1063/1.4790585
关键词: Analytical chemistry 、 Methyl iodide 、 Ionization 、 Thermal desorption 、 Photochemistry 、 Amorphous ice 、 Resonance-enhanced multiphoton ionization 、 Photoionization 、 Photodissociation 、 Amorphous solid 、 Chemistry
摘要: Photodissociation dynamics of methyl iodide (CH3I) adsorbed on both amorphous solid water (ASW) and porous (PASW) has been investigated. The ejected ground-state I(2P3/2) excited-state I(2P1/2) photofragments produced by 260- 290-nm photons were detected using laser resonance-enhanced multiphoton ionization. In contrast to gas-phase photodissociation, (i) the photofragment is favored compared at wavelengths, (ii) have velocity distributions that depend upon ice morphology, (iii) I2 ASW. total iodine [I(2P3/2)+I(2P1/2)+I2] yield varies with substrate greater from ASW than PASW photons. Temperature-programmed desorption studies demonstrate porosity enhances trapping CH3I, while pore-free likely allows monomer adsorption formation two-dimensional CH3I clusters. Reactions or collisions involving these clusters, I atomic fragments, I-containing molecular fragments vacuum-surface interface can result in formation.
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