DBB.01.014

+44 (0) 28 9097 6032

j.kohanoff@qub.ac.uk

Atomistic Simulation Centre School of Mathematics and Physics Queen's University Belfast University Road Belfast BT7 1NN Northern Ireland

- Computer simulation and electronic structure calculations in Condensed Matter, Chemical, and Biological Physics
- Materials under irradiation
- Materials under extreme conditions (high pressures and temperatures)
- Chemical reactivity and proton transfer processes
- Scientific software development

- Electron-phonon thermalization in a scalable method for real-time quantum dynamics,
*Physical Review B*, 2016,**93**, No. 2**doi:**http://dx.doi.org/10.1103/PhysRevB.93.024306**Abstract****Full Text**We present a quantum simulation method that follows the dynamics of out-of-equilibrium many-body systems of electrons and oscillators in real time. Its cost is linear in the number of oscillators and it can probe time scales from attoseconds to hundreds of picoseconds. Contrary to Ehrenfest dynamics, it can thermalize starting from a variety of initial conditions, including electronic population inversion. While an electronic temperature can be defined in terms of a nonequilibrium entropy, a Fermi-Dirac distribution in general emerges only after thermalization. These results can be used to construct a kinetic model of electron-phonon equilibration based on the explicit quantum dynamics. - Understanding the Interaction between Low-Energy Electrons and DNA Nucleotides in Aqueous Solutionhttp://dx.doi.org/http://dx.doi.org/10.1103/PhysRevB.93.024306,
*Journal of Physical Chemistry Letters*, 2015,**6**, No. 15, pp. 3091**doi:**10.1021/acs.jpclett.5b01011**Abstract****Full Text**Reactions that can damage DNA have been simulated using a combination of molecular dynamics and density functional theory. In particular, the damage caused by the attachment of a low energy electron to the nucleobase. Simulations of anionic single nucleotides of DNA in an aqueous environment that was modeled explicitly have been performed. This has allowed us to examine the role played by the water molecules that surround the DNA in radiation damage mechanisms. Our simulations show that hydrogen bonding and protonation of the nucleotide by the water can have a significant effect on the barriers to strand breaking reactions. Furthermore, these effects are not the same for all four of the bases. - Cement As a Waste Form for Nuclear Fission Products: The Case of
^{90}Sr and Its Daughtershttp://dx.doi.org/10.1021/acs.jpclett.5b01011,*Environmental Science & Technology*, 2015**doi:**10.1021/acs.est.5b02609**Abstract****Full Text**One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of^{90}Sr insertion and decay in C–S–H (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold this radioactive fission product and to investigate the consequences of its β-decay on the cement paste structure. We show that^{90}Sr is stable when it substitutes the Ca^{2+}ions in C–S–H, and so is its daughter nucleus^{90}Y after β-decay. Interestingly,^{90}Zr, daughter of^{90}Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Therefore, cement appears as a suitable waste form for ,^{90}Sr storage.

- Computer simulation and electronic structure calculations in Condensed Matter, Chemical, and Biological Physics
- Materials under irradiation
- Materials under extreme conditions (high pressures and temperatures)
- Chemical reactivity and proton transfer processes
- Scientific software development

- Radiation damage in biological systems

With Maeve Smyth, Bin Gu, Emilio Artacho, Fred Currell, David Timson, Eric Suraud and Rodolphe Vuilleumier

- Irradiation of ices on interstellar dust grains

With Emmet McBride, Tom Millar, Tom Field and Bob McCullough

- Irradiation of nuclear materials

With Alfredo Correa, Alfredo Caro, Daniel Sanchez-Portal and Emilio Artacho

- Development of tight-binding models for chemical reactivity in condensed phases

With Tony Paxton, Sasha Lozovoi and Terence Sheppard

- Hydrogen-bonded ferroelectrics

With Giuseppe Colizzi, Sergio Koval, Jorge Lasave, Ricardo Migoni, and Erio Tosatti

- Modelling and simulation of ionic liquids

With Tristan Youngs, Carlos Pinilla, Mario Del Popolo, Claudio Margulis and Ruth Lynden-Bell

- Electronic structure calculations with quantum nuclei

- Ab initio and model Hamiltonian path integral simulations in quantum statistical
mechanics

- Wave function methods for nuclei combined with DFT for electrons

With N. Gidopoulos, Ivan Scivetti, Alfredo Caro and David Hughes

- Ab initio and model Hamiltonian path integral simulations in quantum statistical
mechanics

- First-principles Molecular Dynamics and Monte Carlo

- Hybrid quantum/classical simulations

- Path integral Monte Carlo

- Wave packet propagation

- First-principles path integral simulations

- Electronic structure:

- Pseudopotential PW
- Gaussians
- Pseudopotential LCAO (and order N)