University Lecturer

Alex Thom is a University Professor in Theoretical Chemistry in the University of Cambridge. His research interests are in Theoretical and Computational Chemistry, specializing in method and software development.

Current projects involve the calculation of accurate electronic energies using Monte Carlo techniques, the description of excited states of medium-large molecules (from chromophores to single-molecule magnets) using new methodologies, and the application of Quantum Chemical Algorithms on Quantum Computers.

I am also a developer of the HANDE QMC package (version 1.6 released June 2022) which (amongst many features) performs Full Configuration Interaction Quantum Monte Carlo and Coupled Cluster Monte Carlo on molecular and solid-state systems, and am happy to be contacted with questions about using this or potential applications.

As part of the EXTRA Consortium, we have been looking at the development processes involved in writing scientific software on modern reconfigurable architectures (principally FPGAs), and currently have projects implementing Quantum Monte Carlo methods on these architectures. I am also part of the Cambridge Leverhulme Centre for Life in the Universe.

PhD and MPhil Positions

If you are interested in pursuing an MPhil or PhD in my group, please contact my secretary, sending a CV by email.  Applications to begin October 2025 are now open. For consideration in the funding competition applications must be received by 2nd December 2025.  Applicants with external funding will still be able to apply in early 2026. 

 

I am part of the Centre for Scientific Computing as well as the Leverhulme Centre for Life in the Universe which offer some funded PhD positions, and I am happy to accept applicants for the MPhil in Scientific Computing and also Chemistry. Some example project ideas can be found here.

Dr Thom discusses his research

Publications

Novel H2 activation by a tris[3,5-bis(trifluoromethyl)phenyl]borane frustrated Lewis pair
TJ Herrington, AJW Thom, AJP White, AE Ashley
Dalton transactions (Cambridge, England : 2003)
(2012)
41
Breaking the carbon dimer: The challenges of multiple bond dissociation with full configuration interaction quantum Monte Carlo methods
GH Booth, D Cleland, AJW Thom, A Alavi
The Journal of Chemical Physics
(2011)
135
Stochastic Coupled Cluster Theory
AJW Thom
Phys Rev Lett
(2010)
105
LOBA: a localized orbital bonding analysis to calculate oxidation states, with application to a model water oxidation catalyst.
AJW Thom, EJ Sundstrom, M Head-Gordon
Physical Chemistry Chemical Physics
(2009)
11
Hartree–Fock solutions as a quasidiabatic basis for nonorthogonal configuration interaction
AJW Thom, M Head-Gordon
The Journal of Chemical Physics
(2009)
131
Fermion Monte Carlo without fixed nodes: A game of life, death, and annihilation in Slater determinant space
GH Booth, AJW Thom, A Alavi
The Journal of Chemical Physics
(2009)
131
Locating multiple self-consistent field solutions: an approach inspired by metadynamics.
AJW Thom, M Head-Gordon
Physical review letters
(2008)
101
Electron correlation from path resummations: the double-excitation star.
AJW Thom, GH Booth, A Alavi
Physical chemistry chemical physics : PCCP
(2008)
10
Stochastic perturbation theory: a low-scaling approach to correlated electronic energies.
AJW Thom, A Alavi
Physical review letters
(2007)
99
Path Resummations and the Fermion Sign Problem
A Alavi, AJW Thom
COMPUTER SIMULATIONS IN CONDENSED MATTER SYSTEMS: FROM MATERIALS TO CHEMICAL BIOLOGY, VOL 1
(2006)
703

Head of group

Research Interest Group

Telephone number

01223 336470

Email address

College