Jian-Hao Li

Research

My research interests lie mainly in electronic excitations of molecular systems (bound excitations) and metallic systems (plasmons). To this aim we develop and use novel electronic structure methods to describe the quantum behaviour of electrons in many-electron systems. I have been studying the electronic excitations of both small molecules such as oxirane, which is involved in a photo-induced ring opening reaction, and large systems such as DNA segments and protein molecules, that participate in several interesting excitation-driven processes which nature has evolved over billions of years, such as the ultraviolet light induced damages of DNA molecule and the efficient light-harvesting complexes in photosynthesis.

Quantum mechanics is essential for an appropriate description of the electronic structure and optical properties over hundreds of electrons of a huge system. Density Functional Theory (DFT) for the ground state and the time-dependent DFT (TDDFT) for excited states take centre stage in my research, as they provide reliable yet computationally tractable quantum simulations. I am also interested in developing theoretical methods/techniques incorporating advantages of other theoretical methods such as Many-Body Perturbation Theory and Coupled-Cluster Theory. Fox example, this kind of incorporation has been able to improve upon approximate exchange-correlation functionals used in DFT/TDDFT calculations. Moreover, recent development of linear-scaling (LS) DFT/TDDFT has facilitated the study of ever increasingly large systems. In this regard, we have based our research on the platform of the LS-DFT/TDDFT code ONETEP.