Speaker
Description
The binding energy and desorption pre-exponential factor are key parameters in astrophysical ice chemistry, governing gas-surface processes that ultimately yield the astrophysical observations of a wide variety of gas-phase chemical species in cold environments (e.g., prestellar cores). Without accurate values, contemporary astrochemical models are compelled to rely on wild guesses, often producing misleading results. While the former has been well addressed in recent years by both experimental and computational methods, the latter remains somewhat ill-defined, and different schemes have been proposed in the literature for its evaluation. In the astrochemistry context, binding energies and pre-exponential factors are key parameters that enter microkinetic models for studying the evolution over time of the chemical species in the universe. We focus on these parameters controlling the thermal desorption of ices and how these determine pathways toward molecular complexity and define the location of snowlines, which ultimately influence the planet formation process. We provide binding energies for astrochemically important radicals, alcohols, thiols, and their plausible precursors, as predicted by quantum-chemical computations, with amorphous solid water as the substrate and water as the principal constituent of interstellar ice. Conventional models often rely on single-valued binding energies, overlooking the intrinsic distribution arising from the diversity of adsorption sites. We incorporate a distribution of binding energies to capture the realistic variation in adsorption strengths. Our calculations provide a range of binding energy values rather than just a single estimate. We incorporated our calculated binding energies in astrochemical models, revealing significant effects on predicted molecular abundances.
| Participate the oral/poster presentation award competition | Yes |
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