How do interstellar ices give rise to molecular complexity in space?
Fascinated by the molecular universe and the chemistry that shapes it, my research explores how astrophysically relevant molecules interact with interstellar ice surfaces. Using first-principles quantum chemistry, molecular dynamics, machine learning, and astrochemical modelling, I study binding energies, adsorption environments, and desorption behaviour in heterogeneous icy systems, to improve our understanding of astrochemical evolution in star- and planet-forming regions.
I am building AstroBind, an open-source end-to-end pipeline for computing binding energy distributions of astrophysically relevant species on pure and mixed interstellar ices. AstroBind combines DFT binding energy calculations with the AstroBind-ML XGBoost model, which predicts binding energies from geometric and electronic descriptors of the adsorbate-surface complex, enabling rapid parameterisation for astrochemical modelling. I am extending the dataset beyond amorphous solid water to CO₂, CH₃OH, and mixed ices, as well as N- and S-bearing species, targeting the polar ice inventory revealed by JWST. All models and data will be open-sourced.
Dr Aneesa Ahmad
Research Fellow in Molecular Astrophysics.
University of Leeds
PhD, MChem
Publications
AstroBind: An Open-Source Pipeline for Binding Energy Distributions on Interstellar Ice AnaloguesAhmad, A., Walsh, C.(In prep)Binding Energies of Astrophysically Relevant Molecules on CO2 Ice Clusters: Convergence and BenchmarkingAhmad, A., Walsh, C., Lala, A., Vogt-Geisse, S., and Lamberts, T.(In prep)Beyond geometry: interaction electronic descriptors for machine learning binding energy prediction across hydrogen-bonding and van der Waals interstellar ice speciesAhmad, A., Walsh, C(In prep)AstroBind-ML: Machine learning prediction of binding energy distributions on interstellar water ice from geometric surface descriptorsAhmad, A., Walsh, C(In prep)Theoretical determination of the binding energies of methanol and related species onto amorphous solid water iceAhmad, A., Walsh, C., Vogt-Geisse, S., Silva-Vera, G., and Sainsbury-Martinez, F. The Astrophysical Journal (In revision)Molecular mobility of extraterrestrial ices: surface diffusion in astrochemistry and planetary scienceNFW Ligterink, C Walsh, HM Cuppen, MN Drozdovskaya, A Ahmad, ...Physical Chemistry Chemical Physics 27 (37), 19630-19641Atomic-scale modelling of organic matter in soil: adsorption of organic molecules and biopolymers on the hydroxylated α-Al2O3 (0001) surface A Ahmad, N MartsinovichPhilosophical Transactions of the Royal Society A 381 (2250), 20220254Modelling the strength of mineral–organic binding: organic molecules on the α-Al 2 O 3 (0001) surfaceA Ahmad, N MartsinovichRSC advances 12 (42), 27604-27615