The Thom Group

Professor Alex Thom

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

Understanding and improving the efficiency of full configuration interaction quantum Monte Carlo
WA Vigor, JS Spencer, MJ Bearpark, AJW Thom
The Journal of Chemical Physics
(2016)
144
(doi: 10.1063/1.4943113)
Developments in stochastic coupled cluster theory: The initiator approximation and application to the uniform electron gas
JS Spencer, AJW Thom
The Journal of Chemical Physics
(2016)
144
(doi: 10.1063/1.4942173)
Linked coupled cluster Monte Carlo
RST Franklin, JS Spencer, A Zoccante, AJW Thom
J Chem Phys
(2016)
144
(doi: 10.1063/1.4940317)
Holomorphic Hartree-Fock Theory: An Inherently Multireference Approach.
HGA Burton, AJW Thom
Journal of Chemical Theory and Computation
(2015)
12
(doi: 10.1021/acs.jctc.5b01005)
Minimising biases in full configuration interaction quantum Monte Carlo
WA Vigor, JS Spencer, MJ Bearpark, AJW Thom
J Chem Phys
(2015)
142
(doi: 10.1063/1.4913644)
Open-Source Development Experiences in Scientific Software: The HANDE Quantum Monte Carlo Project
JS Spencer, NS Blunt, WA Vigor, FD Malone, WMC Foulkes, JJ Shepherd, AJW Thom
Journal of Open Ressearch Software
(2015)
3
(doi: 10.5334/jors.bw)
EXTRA: Towards an efficient open platform for reconfigurable High Performance Computing
CB Ciobanu, AL Varbanescu, D Pnevmatikatos, G Charitopoulos, X Niu, W Luk, MD Santambrogio, D Sciuto, M Al Kadi, M Huebner, T Becker, G Gaydadjievll, A Brokalakis, A Nikitakis, AJW Thom, E Vansteenkiste, D Stroobandt
Proceedings IEEE 18th International Conference on Computational Science and Engineering Cse 2015
(2015)
(doi: 10.1109/CSE.2015.54)
Holomorphic Hartree-Fock Theory and Configuration Interaction.
HG Hiscock, AJW Thom
J Chem Theory Comput
(2014)
10
(doi: 10.1021/ct5007696)
Advances in molecular quantum chemistry contained in the Q-Chem 4 program package
Y Shao, Z Gan, E Epifanovsky, ATB Gilbert, M Wormit, J Kussmann, AW Lange, A Behn, J Deng, X Feng, D Ghosh, M Goldey, PR Horn, LD Jacobson, I Kaliman, RZ Khaliullin, T Kuś, A Landau, J Liu, EI Proynov, YM Rhee, RM Richard, MA Rohrdanz, RP Steele, EJ Sundstrom, HL Woodcock, PM Zimmerman, D Zuev, B Albrecht, E Alguire, B Austin, GJO Beran, YA Bernard, E Berquist, K Brandhorst, KB Bravaya, ST Brown, D Casanova, C-M Chang, Y Chen, SH Chien, KD Closser, DL Crittenden, M Diedenhofen, RA DiStasio, H Do, AD Dutoi, RG Edgar, S Fatehi, L Fusti-Molnar, A Ghysels, A Golubeva-Zadorozhnaya, J Gomes, MWD Hanson-Heine, PHP Harbach, AW Hauser, EG Hohenstein, ZC Holden, T-C Jagau, H Ji, B Kaduk, K Khistyaev, J Kim, J Kim, RA King, P Klunzinger, D Kosenkov, T Kowalczyk, CM Krauter, KU Lao, AD Laurent, KV Lawler, SV Levchenko, CY Lin, F Liu, E Livshits, RC Lochan, A Luenser, P Manohar, SF Manzer, S-P Mao, N Mardirossian, AV Marenich, SA Maurer, NJ Mayhall, E Neuscamman, CM Oana, R Olivares-Amaya, DP O’Neill, JA Parkhill, TM Perrine, R Peverati, A Prociuk, DR Rehn, E Rosta, NJ Russ, SM Sharada, S Sharma, DW Small, A Sodt, T Stein, D Stück, Y-C Su, AJW Thom, T Tsuchimochi, V Vanovschi, L Vogt, O Vydrov, T Wang, MA Watson, J Wenzel, A White, CF Williams, J Yang, S Yeganeh, SR Yost, Z-Q You, IY Zhang, X Zhang, Y Zhao, BR Brooks, GKL Chan, DM Chipman, CJ Cramer, WA Goddard, MS Gordon, WJ Hehre, A Klamt, HF Schaefer, MW Schmidt, CD Sherrill, DG Truhlar, A Warshel, X Xu, A Aspuru-Guzik, R Baer, AT Bell, NA Besley, J-D Chai, A Dreuw, BD Dunietz, TR Furlani, SR Gwaltney, C-P Hsu, Y Jung, J Kong, DS Lambrecht, W Liang, C Ochsenfeld, VA Rassolov, LV Slipchenko, JE Subotnik, T Van Voorhis, JM Herbert, AI Krylov, PMW Gill, M Head-Gordon
Molecular Physics
(2014)
113
(doi: 10.1080/00268976.2014.952696)
Choosing RASSCF orbital active spaces for multiple electronic states
F Krausbeck, D Mendive-Tapia, AJW Thom, MJ Bearpark
Computational and Theoretical Chemistry
(2014)
1040
(doi: 10.1016/j.comptc.2014.03.030)

Head of group

Research Interest Group

Telephone number

01223 336470

Email address

ajwt3@cam.ac.uk

College

Peterhouse
Yusuf Hamied Department of Chemistry
Lensfield Road
Cambridge
CB2 1EW
T: +44 (0) 1223 336300
enquiries@ch.cam.ac.uk
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Email: ajwt3@cam.ac.uk
T: 01223 763872

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