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 first-principles calculations with machine learning to predict binding energies from geometric and electronic descriptors of adsorbate–surface complexes, enabling rapid parameterisation for astrochemical models. 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.

Aneesa Ahmad

Research Fellow in Molecular Astrophysics.

University of Leeds

PhD, MChem

Publications

AstroBind: Machine learning prediction of binding energy distributions on interstellar water ice from geometric surface descriptors
Ahmad, A., Walsh, C
(submitted to ApJ)
Theoretical determination of the binding energies of methanol and related species onto amorphous solid water ice
Ahmad, A., Walsh, C., Vogt-Geisse, S., Silva-Vera, G., and Sainsbury-Martinez, F. 
The Astrophysical Journal 1006 (2), 225
Molecular mobility of extraterrestrial ices: surface diffusion in astrochemistry and planetary science
NFW Ligterink, C Walsh, HM Cuppen, MN Drozdovskaya, A Ahmad, ...
Physical Chemistry Chemical Physics 27 (37), 19630-19641
Atomic-scale modelling of organic matter in soil: adsorption of organic molecules and biopolymers on the hydroxylated α-Al2O3 (0001) surface 
A Ahmad, N Martsinovich
Philosophical Transactions of the Royal Society A 381 (2250), 20220254