Molecular Balances: Computation meets Experiment

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- the research questions the project is trying to address/the objectives of the project; Molecular balances are relatively small systems designed to experimentally isolate a given type of interaction, and to what extent it is responsible for the behaviour of the total system. While the experimental literature on molecular balances steadily grows, its theoretical and computational counterpart is woefully underdeveloped. The overall objective is to fundamentally change this unacceptable situation. More specific objectives are:- apply the energy partitioning method Interacting Quantum Atoms (IQA) on well-studied named balances (e.g. Cockroft, Gung, Shimizu) using DFT with external dispersion correction (D3, D4).- enable the incorporation of non-DFT post-Hartree-Fock wavefunctions in the IQA-compatible evaluation of dispersion energy by linking the two-particle-density-matrix (2PDM) electron correlation energies to one-particle-density-matrix (1PDM) ones.- apply the in-house method Relative Energy Gradient (REG) to rank energy contributions by their importance in explaining the system's overall behaviour.- apply the in-house force field FFLUX on a selection of molecular balances in aqueous solution and monitor partitioned energy trajectories with REG-IQA. Study the corresponding multipolar electrostatics. - Use the developed methodology and acquired knowledge to obtain chemical insight in foldamers and, ambitiously, start guiding their synthetic design.- the approach that will be taken to answer these questions (what the student will actually be doing); The student will benefit from the precise combination of three main methodologies: IQA, REG and FFLUX. The realism and sophistication following from this "cross-fertilising" combination will offer unprecedented insight into molecular balances. This work will thereby deliver the much needed computational counterpart to the literature mentioned above. The student will make efficient use of the computer programs but will need to write specific Python scripts to handle the wealth of data that the local computers will generate. He will also use the machine learning method Gaussian Process Regression to create models from which the atomic energies can be quickly calculated. As a further type of activity, the student will find a pattern between the 2PDM (the reference or "calibrator") and the 1PDM, which is the only computationally feasible approach to obtain IQA-compatible non-DFT electron correlation energies and thus dispersion energy. Finally, the student will carry out some programming in FORTRAN90, in order to modify DL-FFLUX so that it can handle IQA-based dispersion energies. - the novel engineering and/or physical sciences content of the research (the science that places it within EPSRC's remit). Overall the project fits under two sub-portfolios of the Theme Physical Sciences, namely "Computational and Theoretical", and "Condensed Matter: Electronic Structure" with an ultimate connection to Supramolecular Chemistry. This project also resorts under the Chemical Sciences Grand Challenge of Directed Assembly of Extended Structures with Targeted Properties (DAESTP). Finally, there is a strong Machine Learning component to this project, and thus overlap with Artificial Intelligence.