We use theory (mostly toy models) and computation (from DFT to quantum computer-friendly algorithms) to understand molecules and materials, and to make predictions about them. We have two broad areas of interest:

1. Electronic structure of π-conjugated systems

π-conjugated systems bridge the gap between metals, in which electrons are free, and ordinary molecules, in which electrons are localised. This delocalisation results in tuneable optical properties, making π-conjugated systems appealing for optoelectronics, e.g. for OLEDs and solar cells. From a fundamental perspective, π-conjugation is interesting because it enables quantum behaviour, such as induced ring currents, quantum interference, length-independent conductance.

We are interested in answering questions such as:

• What is the maximum size that a molecule can be and still exhibit quantum behaviour? Can we bend the π-system into new topologies, unlocking exotic phases and non-trivial states of matter?
• How do spins communicate through aromatic or anti-aromatic motifs? Can we design candidates for qubits in which the magnetic coupling can be controlled optically or electrochemically?
• Can we design single-molecule devices that benefit from quantum interference? Can we use topology or spin as an unconventional degree of freedom to switch between constructive and destructive interference?
• Can we understand these phenomena by tight-binding models or effective Hamiltonians? How do we make sure our predictions are correct? Can quantum computers help?

To answer these questions, we collaborate with world-leading groups in organic synthesis (Harry Anderson, Oxford; Diego Peña, Santiago de Compostela, Spain), scanning probe microscopy (Leo Gross, IBM Research, Switzerland), and quantum computing (Ivano Tavernelli, IBM Quantum, Switzerland).

1. Modern physical-organic chemistry

We are also interested in dynamic processes governed by non-statistical effects or external forces, answering questions such as:

Can we enhance catalysis using an electric field? Can we unlock strange new reactions by using an external (mechanochemical) force? How do the electronic properties (e.g. the band gap) of materials change on a femtosecond scale? Which vibrations (phonons) are relevant? To answer these questions, we build toy models and perform ab initio molecular dynamics simulations, collaborating with mechanochemists (Guillaume De Bo, Manchester), organic chemists (Keith Andrews, Durham), and theoreticians (Pavel Jungwirth, Institute of Organic Chemistry and Biochemistry, Czechia).