Dr Keith Hughes

My area of research is theoretical and concentrates on the quantum dynamical aspect of molecular processes. Motivation for this work is driven by the desire to gain deep insight and understanding of molecular behaviour at the most detailed level. I am involved with the development of new theoretical and computational methods in quantum dynamics, and in the application of these methods to key areas of chemical interest, such as:

• Charge and energy transfer in materials and biological systems
• Solvation dynamics

I am willing to supervise a PhD

Quantum dynamics in large complex environments

The quantum dynamics of large complex molecular systems on an ultrafast (femtosecond) timescale necessitates the use of reduced non-Markovian master equations or else an explicit treatment of the molecular sub-system and environment is required. We use the recently developed hierarchical effective-mode approach (see publications list) to study the quantum dynamics of complex molecular systems. The approach enables an accurate representation of the sytem-environment dynamics to be constructed and allows for more controlled approximations to the system-environment description to be made. The method has wide range of applications including energy transfer in DNA, gas-surface processes and charge and energy transfer processes in materials such as organic devices.  

Example: Non-Markovian reduced dynamics of ultrafast charge transfer at an oligothiophene-fullerene heterojunction, K. H. Hughesm, B. Cahier, R. Martinazzo, H. Tamura and I. Burghardt, Chem. Phys. 442, 111, (2014). (FEMTO 11 special issue) DOI: 10.1016/j.chemphys.2014.06.015

Mixed quantum-classical approach to non-equilibrium solvation

Attention here is focussed on the development of a mesoscopic mixed quantum-classical description of non-equilibrium solvation that goes beyond the dynamical density functional theory (DDFT) level. The method is applicable for studying a wide range of transport and solvation processes. Quantum coherence effects are fully captured by the approach, making it suitable for studying long-lived coherences in large biological systems, for example, excitation energy transfer in photosynthetic systems.

2019

• Vibronic coupling models for donor-acceptor aggregates using an effective-mode scheme: Application to mixed Frenkel and charge-transfer excitons in oligothiophene aggregates
  
  Hughes, K, Burghardt, I, Wjatscheslaw, P, Polkehn, M & Martinazzo, R 2019, 'Vibronic coupling models for donor-acceptor aggregates using an effective-mode scheme: Application to mixed Frenkel and charge-transfer excitons in oligothiophene aggregates', Journal of Chemical Physics, vol. 150, no. 24, 244114.

2015

• Quantum dynamics of hydrogen atoms on graphene. I. System-bath modeling
  
  Bonfanti, M, Jackson, B, Hughes, KH, Burghardt, I & Martinazzo, R 2015, 'Quantum dynamics of hydrogen atoms on graphene. I. System-bath modeling', Journal of Chemical Physics, vol. 143, no. 124703. https://doi.org/10.1063/1.4931116
• Quantum dynamics of hydrogen atoms on graphene. II. Sticking
  
  Bonfanti, M, Jackson, B, Hughes, KH, Burghardt, I & Martinazzo, R 2015, 'Quantum dynamics of hydrogen atoms on graphene. II. Sticking', Journal of Chemical Physics, vol. 143, no. 1124704. https://doi.org/10.1063/1.4931117
• Vibrational relaxation and decoherence in structured environments: a numerical investigation
  
  Bonfanti, M, Hughes, KH, Burghardt, I & Martinazzo, R 2015, 'Vibrational relaxation and decoherence in structured environments: a numerical investigation', Annalen der Physik. https://doi.org/10.1002/andp.201500144

2014

• Non-Markovian reduced dynamics of ultrafast charge transfer at an oligothiophene–fullerene heterojunction
  
  Hughes, KH, Cahier, B, Martinazzo, R, Tamura, H & Burghardt, I 2014, 'Non-Markovian reduced dynamics of ultrafast charge transfer at an oligothiophene–fullerene heterojunction', Chemical Physics, vol. 442, pp. 111-118. https://doi.org/10.1016/j.chemphys.2014.06.015

2012

• Non-Markovian reduced dynamics based upon a hierarchical effective-mode representation
  
  Burghardt, I, Matinazzo, R & Hughes, KH 2012, 'Non-Markovian reduced dynamics based upon a hierarchical effective-mode representation', Journal of Chemical Physics, vol. 137, no. 14, pp. Article 144107. https://doi.org/10.1063/1.4752078
• Compact MCTDH Wave Functions for High-Dimensional System-Bath Quantum Dynamics
  
  Bonfanti, M, Tantardini, GF, Hughes, KH, Martinazzo, R & Burghardt, I 2012, 'Compact MCTDH Wave Functions for High-Dimensional System-Bath Quantum Dynamics', Journal of Physical Chemistry C, vol. 116, no. 46, pp. 11406-11413. https://doi.org/10.1021/jp3064504
• Maximum-entropy closure of hydrodynamic moment hierarchies including correlations
  
  Hughes, KH & Burghardt, I 2012, 'Maximum-entropy closure of hydrodynamic moment hierarchies including correlations', Journal of Chemical Physics, vol. 136, no. 21, pp. Article 214109. https://doi.org/10.1063/1.4720568
• Extended hydrodynamic approach to quantum-classical nonequilibrium evolution. II. Application to nonpolar solvation
  
  Hughes, KH, Baxter, S, Bousquet, D, Ramanathan, P & Burghardt, I 2012, 'Extended hydrodynamic approach to quantum-classical nonequilibrium evolution. II. Application to nonpolar solvation', Journal of Chemical Physics, vol. 136, no. 1, 014102. https://doi.org/10.1063/1.3671378, https://doi.org/10.1063/1.3671378

2011

• Unraveling a Brownian particle’s memory with effective mode chains
  
  Martinazzo, R, Hughes, KH & Burghardt, I 2011, 'Unraveling a Brownian particle’s memory with effective mode chains', Physical Review E, vol. 84, no. 3, pp. Article 030102. https://doi.org/10.1103/PhysRevE.84.030102
• Extended hydrodynamic approach to quantum-classical nonequilibrium evolution. I. Theory
  
  Bousquet, D, Hughes, KH, Micha, DA & Burghardt, I 2011, 'Extended hydrodynamic approach to quantum-classical nonequilibrium evolution. I. Theory', Journal of Chemical Physics, vol. 134, no. 6, pp. Article 064116. https://doi.org/10.1063/1.3553174
• Universal Markovian reduction of Brownian particle dynamics.
  
  Martinazzo, R, Vacchini, B, Hughes, KH & Burghardt, I 2011, 'Universal Markovian reduction of Brownian particle dynamics.', Journal of Chemical Physics, vol. 134, no. 1, pp. 011101. https://doi.org/10.1063/1.3532408

2010

• Effective spectral densities for system-environment dynamics at conical intersections: S2-S1 conical intersection in pyrazine.
  
  Martinazzo, R, Hughes, KH, Martelli, F & Burghardt, I 2010, 'Effective spectral densities for system-environment dynamics at conical intersections: S2-S1 conical intersection in pyrazine.', Chemical Physics, vol. 377, no. 1-3, pp. 21-29. https://doi.org/10.1016/j.chemphys.2010.08.010
• A hybrid hydrodynamic lliouvillian approach to non-Markovian dynamics.
  
  Hughes, KH, Burghardt, I & Chattaraj, P (ed.) 2010, A hybrid hydrodynamic lliouvillian approach to non-Markovian dynamics. in Quantum Trajectories. 2010 edn, Taylor and Francis.

2009

• Effective-mode representation of non-Markovian dynamics: A hierarchical approximation of the spectral density. II. Application to environment-induced nonadiabatic dynamics.
  
  Hughes, KH, Christ, CD & Burghardt, I 2009, 'Effective-mode representation of non-Markovian dynamics: A hierarchical approximation of the spectral density. II. Application to environment-induced nonadiabatic dynamics.', Journal of Chemical Physics, vol. 131, no. 12, pp. 124108. https://doi.org/10.1063/1.3226343
• Effective-mode representation of non-Markovian dynamics: A hierarchical approximation of the spectral density. I. Application to single surface dynamics.
  
  Hughes, KH, Christ, CD & Burghardt, I 2009, 'Effective-mode representation of non-Markovian dynamics: A hierarchical approximation of the spectral density. I. Application to single surface dynamics.', Journal of Chemical Physics, vol. 131, no. 2, pp. 024109. https://doi.org/10.1063/1.3159671
• Closure of quantum hydrodynamic moment equations.
  
  Hughes, KH, Parry, SM & Burghardt, I 2009, 'Closure of quantum hydrodynamic moment equations.', Journal of Chemical Physics, vol. 130, no. 5, pp. 054115. https://doi.org/10.1063/1.3073759
• Quantum hydrodynamics for mixed states.
  
  Hughes, KH, Parry, SM, Burghardt, I, Shalashilin, DV (ed.) & De Miranda, MP (ed.) 2009, Quantum hydrodynamics for mixed states. in Multidimensional Quantum Mechanics with Trajectories. 2009 edn, CCP, Daresbury, pp. 74-76.

2007

• A hybrid hydrodynamic-liouvillian approach to mixed quantum-classical dynamics: application to tunneling in a double well
  
  Hughes, KH, Parry, SM, Parlant, G & Burghardt, I 2007, 'A hybrid hydrodynamic-liouvillian approach to mixed quantum-classical dynamics: application to tunneling in a double well', Journal of Physical Chemistry A, vol. 111, no. 41, pp. 10269-10283. https://doi.org/10.1021/jp072642f
• Quantum hydrodynamics and a new approach to mixed quantum-classical theory.
  
  Burghardt, I, Moller, KB, Hughes, KH & Micha, DA (ed.) 2007, Quantum hydrodynamics and a new approach to mixed quantum-classical theory. in Quantum Dynamics of Complex Molecular Systems. 2007 edn, Springer, pp. 391-422.

2006

• Dynamics of Open Quantum Systems
  
  Hughes, KH (ed.) 2006, Dynamics of Open Quantum Systems. 2006 edn, CCP, Daresbury.
• Optical control of dissipative quantum phase space dynamics.
  
  Hughes, KH, Hywel. M.*, NV, Lasorne, B (ed.) & Worth, GA (ed.) 2006, Optical control of dissipative quantum phase space dynamics. in Coherent Control of Molecules. 2006 edn, CCP, Daresbury, pp. 28-33.

2005

• Dissipative quantum phase space dynamics on dynamically adapting grids.
  
  Hughes, KH 2005, 'Dissipative quantum phase space dynamics on dynamically adapting grids.', Journal of Chemical Physics, vol. 122, no. 7, pp. 074106-074117. https://doi.org/10.1063/1.1847609

2004

• Trajectory approach to dissipative quantum phase space dynamics: application to barrier scattering
  
  Hughes, KH & Wyatt, RE 2004, 'Trajectory approach to dissipative quantum phase space dynamics: application to barrier scattering', Journal of Chemical Physics, vol. 120, no. 9, pp. 4089-4097. https://doi.org/10.1063/1.1643897

2003

• A new method for wave packet dynamics: derivative propagation along quantum trajectories
  
  Trahan, CJ, Hughes, KH & Wyatt, RE 2003, 'A new method for wave packet dynamics: derivative propagation along quantum trajectories', Journal of Chemical Physics, vol. 118, no. 22, pp. 9911. https://doi.org/10.1063/1.1578061
• Torsion-rotation interactions in monodeuterated acetaldehyde
  
  Cox, AP, Hughes, KH & Macdonald, J 2003, 'Torsion-rotation interactions in monodeuterated acetaldehyde', Molecular Physics, vol. 101, no. 4-5, pp. 569-574. https://doi.org/10.1080/0026897021000021868
• Wavepacket dynamics on arbitrary Lagrangian-Eulerian grids: application to an Eckart barrier
  
  Hughes, KH & Wyatt, RE 2003, 'Wavepacket dynamics on arbitrary Lagrangian-Eulerian grids: application to an Eckart barrier', Physical Chemistry Chemical Physics, vol. 5, no. 18, pp. 3905-3910. https://doi.org/10.1039/b305638d

2002

• Wavepacket dynamics on dynamically adapting grids: application of the equidistribution principle
  
  Hughes, KH & Wyatt, RE 2002, 'Wavepacket dynamics on dynamically adapting grids: application of the equidistribution principle', Chemical Physics Letters, vol. 366, no. 3-4, pp. 336-342. https://doi.org/10.1016/S0009-2614(02)01654-8

2000

• Boltzmann wavepacket dynamics on periodic molecular potential functions.
  
  Hughes, KH & Macdonald, JN 2000, 'Boltzmann wavepacket dynamics on periodic molecular potential functions.', Physical Chemistry Chemical Physics, vol. 2, no. 19, pp. 4267-4273. https://doi.org/10.1039/b004360p
• Boltzmann wavepacket dynamics of tunnelling of molecules through symmetric and asymmetric energy barriers on non-periodic potential functions.
  
  Hughes, KH & Macdonald, JN 2000, 'Boltzmann wavepacket dynamics of tunnelling of molecules through symmetric and asymmetric energy barriers on non-periodic potential functions.', Physical Chemistry Chemical Physics, vol. 2, no. 16, pp. 3539-3547. https://doi.org/10.1039/b002675l