Research Fellows Directory
Fidel Alejandro Batista Romero
Dr Fidel Alejandro Batista Romero
University of Bristol
Enormous progress has been made in the development of quantum embedding theories that allow a small, important region to be modelled to high accuracy, even when it is connected to a complex chemical environment. Quantum embedding techniques go beyond the framework of the Nobel-prize-winning QM/MM framework by allowing coupling between system and environment to take account of quantum effects such as dispersion, exchange-repulsion and entanglement. Examples of systems where strong coupling to the environment plays an important role include in enzymological problems with active sites covalently bound to a larger protein environment; problems in surface science where reactivity or excitations of molecules take place near semi-conductor or metal surfaces; and in cases such as homogeneous transition-metal catalysis where the complexities of the electronic structure demand system partitions that cut very close to the reactive centre.
The aim of my work is to develop a novel embedding framework that captures the polarisation and screening effects that an environment exerts on excited states of a small subsystem. Electronic excitations in a chromophore in solution, or in a defect or impurity in a solid, invariably entail redistribution of electronic charge. In concert with this effect the environment adjusts to the new electronic state of the impurity, and this reorganisation is characterised by a slow component (in which ions or polar molecules rearrange themselves to stabilise the excited state of the impurity) and a fast component that arises from electronic reorganisation in the environment.
Interests and expertise (Subject groups)