Binding energy of biomolecules on ice-covered grains in the interstellar medium

Project Description

The discovery of glycine, one of the most basic amino acid, on comet 67P/Churyumov-Gerasimenko by Rosetta ESA mission has sparked interest in studying the adsorption of molecules of biological interest on interstellar ices. Unfortunately, there is currently a lack of accurate data on the binding energy of biomolecules on ice. This, in turn, renders the estimation of the abundance of biomolecules on icy grains (dust or comets) unreliable for most chemical network approaches. In this study, we plan to determine reliable binding energy for representative biomolecules (glycine, formic acid, acetonitrile) using a mixed density functional / quantum mechanical approach. Our technique combines a periodic density functional description of the ice layer with a quantum chemical ansatz for the adsorbed molecule. We have already shown this approach to be successful for a number of aromatic molecules on an ice surface (unpublished results) and our results compare well to the available measure thermal desorption laboratory data. The impact of the data obtained in this project can be explored in a larger astrophysics contact with the results incorporated in cosmochemistry network simulations developed at the Milne centre (David Beniot (L), Marco Pignatari (L), Jacob Tomassi (MSc)). This will also allow the student to get a direct experience of multi-disciplinary research.

This project is part of a new research effort of the E.A. Milne centre for astrophysics at the University of Hull that focusses on understanding the astrochemistry of deposited molecules. The Milne Centre was established in 2015 to spearhead research, teaching and outreach activities within physics at the University of Hull. This provides an excellent working environment which includes not only the staff and postgraduates but also a vibrant visitor programme, and strong scientific and social links to undergraduates through the Physics Society. Additionally £2M was invested in 2016 to provide a peerless High Performance Computing infrastructure (VIPER) with 5,500 cores, with 90% usage allocated to the Milne Centre staff and students. The facility will be core to the success of this project.

During the bursary, the student will be able to develop their computational skills and learn state-of-the-art techniques in computational chemistry, high-performance computing and astrochemistry. The results of the binding energy calculations will form a database that will be used in our latest grain models, delivering unprecedented improved accuracy to study deposition phenomena on interstellar grains and comets.