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Yusuf Hamied Department of Chemistry


Professor of Theoretical Chemistry

What we do...

Our theoretical research group uses mathematical and computational techniques to investigate quantum behaviour in the motion of atomic nuclei. We carry out computer simulations which illustrate how quantum mechanics changes the motion of atoms and molecules in chemical reactions and inside liquid water and ice.


Our research investigates how the quantum properties of atomic nuclei affect chemical reaction rates and mechanisms. We develop and apply a wide range of theories and computational techniques, from exact solutions of the Schrödinger equation for small systems, to approximate Feynman path- integral approaches for larger systems.

First-principles calculations of wave functions of chemical reactions

We were the first group to calculate a complete time-dependent wave function that visualizes the entire dynamics of a chemical reaction from approach of the reactants through to scattering of the products into space. This work is done in collaboration with a leading experimental group (R.N. Zare, Stanford) who measure detailed product-scattering patterns that our calculations reproduce and interpret in terms of first-principles quantum mechanics.

Instanton simulations of quantum tunnelling

Instantons arise when Feynman path-integral theory is used to describe quantum tunnelling through barriers; they describe the dominant tunnelling path, which gives an approximate but physically rigorous description of the tunnelling dynamics. We have recently developed and extended instanton theory such that the instantons are represented by a series of beads which can be rapidly strung together to describe quantum tunnelling in complex systems. We are currently applying this method to tunnelling in water clusters (in collaboration with Prof. D.J. Wales), and to proton transfer reactions in solution.

Winding effects at conical intersections

Conical intersections arise when potential energy surfaces intersect. We have found that the nuclear wave functions at such intersections can be unwound, such that contributions from Feynman paths that wind different numbers of times around the intersection can be rigorously separated. This gives rise to quantum interference effects; we are currently investigating how such effects influence the efficiency of relaxation through a conical intersection.

Watch Professor Althorpe discuss his research


Instantons and the quantum bound to chaos
VG Sadhasivam, L Meuser, DR Reichman, SC Althorpe
– Proc Natl Acad Sci U S A
Comparison of Matsubara dynamics with exact quantum dynamics for an oscillator coupled to a dissipative bath
A Prada, ES Pós, SC Althorpe
– Journal of Chemical Physics
Improved torque estimator for condensed-phase quasicentroid molecular dynamics
G Trenins, C Haggard, SC Althorpe
– The Journal of Chemical Physics
Testing the quasicentroid molecular dynamics method on gas-phase ammonia
C Haggard, VG Sadhasivam, G Trenins, SC Althorpe
– The Journal of Chemical Physics
On the "Matsubara heating" of overtone intensities and Fermi splittings.
RL Benson, SC Althorpe
– Journal of Chemical Physics
Path-integral approximations to quantum dynamics
SC Althorpe
– The European Physical Journal B
Which quantum statistics–classical dynamics method is best for water?
RL Benson, G Trenins, SC Althorpe
– Faraday Discuss
Zero-point energy and tunnelling: General discussion
SC Althorpe, AM Alvertis, W Barford, RL Benson, I Burghardt, S Giannini, S Habershon, S Hammes-Schiffer, S Hay, S Iyengar, A Kelly, K Komarova, J Lawrence, Y Litman, C Martens, RJ Maurer, D Plant, M Rossi, K Sakaushi, A Schile, S Sturniolo, DP Tew, G Trenins, G Worth
– Faraday Discussions
Tunneling Splittings in Water Clusters from Path Integral Molecular Dynamics
CL Vaillant, DJ Wales, SC Althorpe
– J Phys Chem Lett
Path-integral dynamics of water using curvilinear centroids
G Trenins, MJ Willatt, SC Althorpe
– Journal of Chemical Physics
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Research Group

Research Interest Group

Telephone number

01223 336373

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