# Research

## Students wanted

We are looking for Master and PhD students! Projects in our group have broadly three components:

- Mathematical development of equations to be solved (a familiarity with linear algebra is very beneficial)
- Computer programming (mostly python and fortran90) of equations to be solved
- Computing solutions to chemical problems

Interested students should send me an email directly, preferably with a CV and transcript of grades.

# Strong Electron Correlation

As with any complicated mathematical problem, our understanding of electronic structure is based on first approximating with a simple problem, which we can solve exactly, and adding small corrections to account for the deviations from the simple model. The established methods of quantum chemistry are based on a picture of noninteracting electrons. For a large portion of chemistry, non-interacting electrons are a good starting point. Indeed any system which is qualitatively described by **one **molecular-orbital diagram will be well described by Density Functional Theory or Coupled Cluster Theory. Systems which require **many **molecular orbital diagrams for a correct qualitative description are not well treated by the popular methods. DMRG and Slater determinant Monte Carlo describe these systems well, but are generally too expensive.

Our approach is to to break the problem into an easy problem we can solve, and small corrections for the deviations. No one model will solve every chemical problem, so we are working on many to account for different situations. Our starting point is exactly solvable (or integrable) models, such as Richardson-Gaudin, Heisenberg, Hubbard, etc.

# Chemical Modelling

We have numerous collaborations with colleagues in the Chemistry department. We study reaction mechanisms, locate transition states, calculate molecular properties etc.

**Mario Leclerc:**Polymerization catalysis and solar cells**Jean-François Morin:**Molecular electronics**Denis Giguère:**Medicinal chemistry**Jean-François Paquin:**Organofluorine chemistry**Thierry Ollevier:**Synthesis and green chemistry

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