PhD Thesis under Prof. Sarah L. Price [UCL] & Dr. Alston Misquitta [QMUL]
Testing and further developing the theory behind intermolecular force-fields.
Improving on the workflows and programs that are currently being utilized by research groups in the field of Crystal Structure Prediction (CSP).
Developing bespoke, realistic non-empirical atom-atom force-field and new workflows to generate these potentials to accurately model the behaviour of weakly-bound organic molecules.
Increasing the accessibility and transferability of these force-fields between codes and organic systems.
These force-fields are suitable for modelling not only gas-phase dimer interactions but also crystal polymorphs and their physical properties, reliably, under conditions typically inaccessible by contemporary empirical treatments.
Alexander A. Aina, Alston J. Misquitta & Sarah L. Price
Investigating the effect of nitro-group charge distributions on polymorphism and the physical properties of organic energetic materials using the ISA partitioning treatment.
The effects of changing conformation (torsion angle) and neighbouring atom environment was also studied. The electrostatic properties of the molecule and thus the crystal were greatly affected by these changes.
The report also investigated the resultant effect on previously proposed correlations between molecular electrostatic properties and energetic properties, such trigger-bond potential, electrostatic potential maxima and impact sensitivity.
We examined the effect of analytically rotating the atomic multipole moments to model changes in torsion angle and establish that this is a viable approach for Crystal Structure Prediction (CSP) but is not accurate enough to model relative lattice energies.
Alexander A. Aina, Alston J. Misquitta & Sarah L. Price
The study focused on modelling pyridine's crystal structures using an anisotropic force-field. The potential used distributed atomic multipoles, polarizabilities, and dispersion coefficients and an anisotropic atom-atom repulsion model derived from SAPT(DFT) dimer calculations.
We show that these distributed intermolecular force-fields (DIFFs) accurately model the pyridine experimental crystal structures. The differences in crystal structures are comparable with changes in temperature, pressure, or the neglect of zero-point vibrational effects.
The newly developed DIFFÂ model was able to identify not only the observed polymorphs of pyridine in a CSPÂ study but also the structure of an unreported high pressure phase of pyridine (Form III), which empirical fitted potentials were unable to find.
The work highlights the complexity in modelling crystallization phenomena from a realistic atom-atom potential energy surface
4th Year MSci Project under Prof. Alexei Kornyshev [ICL]
A study stemming from earlier work by Professor Alexei Kornyshev. The masters project at Imperial College London focused on understanding the charging behaviour in cylindrical nano-porous electrodes filled with a single, symmetric ionic layer. Numerical and analytical analysis of a non-trivial single dimension 2 spin Ising model showcases the variation of the potential dependence of capacitance, charge storage and accumulation with pore dispersion and counter-ion asymmetry. Dynamics utilising a transmission line model assists in describing the accumulation of charge and the power and energy densities in these cylindrical super-capacitors for differing pore distributions and counter-ion combinations.
UROP & Literature Review under Prof. Nic Harrison [ICL]
The UROP involved a simulative study of point defects in Graphene
The literature review on the current [at the time] CMOS devices and methods of computing beyond the silicon chip.
Silicon chips are used in all modern electronic devices to date. Transistors are the active component in conventional silicon chips, governing the communication, processing and storage capabilities of modern devices. The report investigated the then current technologies likely to be used in the near future to replace current CMOS devices. The report also explored spintronics and gave a small insight into the world of quantum computing, a phenomenon that could take computing architecture as well as artificial intelligence to the upper limit of human imagination.