# Ab initio methods for electronic charge-transfer

Research Group:Centre for Condensed Matter and Material Physics

Number of Students:1

Length of Study in Years: 3

Full-time Project: yes

Funding:

QM Scholarship

Project Description:

The phenomenon of electronic charge transfer is important both scientifically and technologically as it is the mechanism through which energy is produced in our cells and in batteries. You might say that charge-transfer, perhaps more appropriately called charge delocalisation, is the on-set of chemical bonding. Species A interacts with species B leading to a partial change in partial charges and the movement of charge from one location to another: this is energy storage and it underlies some of the major challenges we face today. But, this phenomenon occurs in complex environments and is notoriously difficult to model. The only ab initio methods (methods that start from the Schrodinger equation) that can be applied to large systems is density-functional theory (DFT), but one of the biggest shortcomings of DFT is its inability to accurately model the charge-transfer process.

In this project, we will build on the very detailed understanding of intermolecular interactions we have in my group (through symmetry-adapted perturbation theory (SAPT) [1]) and very recent progress I have made in rigorously defining the charge-transfer energy [2] to develop rigorous definitions of the charge-transfer within DFT, and to eventually use simplified analytical methods to develop a model for the charge-transfer energy that will be applicable in semi-classical simulations. These models, if successful, could transform the way simulations are performed and lead to new and exciting discoveries.

Day-to-Day: This project will mix, in equal parts, theory, programming, and applications/data analysis. One of the outcomes will be a substantially large program that will allow the models developed to be implemented in the CamCASP suite of programs. There is a lot of theoretical background needed and the student will need to become comfortable with modern electronic structure methods. There will be at least two conferences to attend and at least three papers to be written. So good writing and communication skills are welcome.

[1] A. J. Misquitta, R. Podeszwa, B. Jeziorski, and K. Szalewicz, Intermolecular potentials based on symmetry-adapted perturbation theory with dispersion energies from time-dependent density functional calculations.'', J. Chem. Phys., {\bf 123}, 214103-14 (2005).

[2] A. J. Misquitta, Charge-transfer from Regulrized Symmetry-Adapted Perturbation Theory'', J. Chem. Theory. Comput. (2013), DOI: 10.1021/ct400704a

Requirements:

Intermediate programming skills in Fortran90 or Python or C/C++
Good mathematical background.
Some level of understanding of electronic structure methods like Hartree-Fock and Density Functional Theory will help.