Vorschau

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Abstract

To date more than 170 species have been identified in interstellar space, and the chemical processes that govern their formation and destruction are driven by thousands of reactions connecting hundreds of atomic and molecular species. The study of these species give us essential information on the physical and chemical processes of astrophysical environments. Studies of deuterated species give us important clues also on the chemical ages and thermal history of these environments. As we enter a new exciting era with highly sensitive measurements of the chemical cosmos provided by ALMA, there is a need for new sophisticated models to analyze the forthcoming wealth of data.

The purpose of this thesis is to develop a sophisticated chemical model for studying the deuterium chemistry, benchmark it and its uncertainties and to utilize it to model increasingly more complex star-formation environments. We benchmark the deuterium chemistry model by comparing the calculated to observed D/H ratios of a variety of mono-, doubly-, and triply-deuterated species in distinct astrophysical environments. Uncertainties in abundances and D/H ratios are quantified by a sensitivity analysis, and the most problematic reactions are also identified to aid future laboratory experiments.

Ortho-para chemistry has been found to have a profound effect on the pace of deuterium fractionation. The ortho-para model is developed and used successfully to study the para-fractions in diffuse clouds where we improve our understanding of the underlying chemistry of H3+ and H2. Finally, high-temperature reactions are added to the network and used in a study of the origin of Earth's ocean water and the water in primitive bodies of the Solar system (comets and asteroids).