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Thomas James Penfold

Cette personne n’est plus à l’EPFL

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Publications associées (36)

X-ray Absorption Spectroscopy of Ground and Excited Rhenium–Carbonyl–Diimine Complexes: Evidence for a Two-Center Electron Transfer

Majed Chergui, Ursula Röthlisberger, Ivano Tavernelli, Amal El Nahhas, Van Thai Pham, Renske Marjan van der Veen, Frederico Alves Lima, Thomas James Penfold

Steady-state and picosecond time-resolved X-ray absorption spectroscopy is used to study the ground and lowest triplet states of ReX(CO)(3)(bpy), X = Etpy (n = 1), Cl, or Br (n = 0). We demonstrate that the transient spectra at both the Re L3- and Br ...

Amer Chemical Soc2013

Solvent rearrangements during the transition from hydrophilic to hydrophobic solvation

Majed Chergui, Ursula Röthlisberger, Ivano Tavernelli, Manuel Dömer, Thomas James Penfold

We present an ab initio Born-Oppenheimer molecular dynamics study of the early time solvent dynamics after electron abstraction from aqueous iodide. An initial response occurs within ∼75 fs, corresponding to a water molecule sharing almost one electron wit ...

Elsevier2013

Local Control Theory using Trajectory Surface Hopping and Linear-Response Time-Dependent Density Functional Theory

Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Thomas James Penfold

The implementation of local control theory using nonadiabatic molecular dynamics within the framework of linear-response time-dependent density functional theory is discussed. The method is applied to study the photoexcitation of lithium fluoride, for whic ...

Schweizerische Chemische Gesellschaft2013

Solvent Induced Luminescence Quenching: Static and Time-Resolved X-Ray Absorption Spectroscopy of a Copper(I) Phenanthroline Complex

Majed Chergui, Olivier Christian Bräm, Ursula Röthlisberger, Ivano Tavernelli, Frederico Alves Lima, Marco Eli Reinhard, Mercedes Hannelore Rittmann-Frank, Thomas James Penfold, Lotta Susanne Karlsson, Jochen Rittmann, Gloria Capano

We present a static and picosecond X-ray absorption study at the Cu K-edge of bis(2,9-dimethyl-1,10-phenanthroline)copper(I) (Cu(dmp)(2); dmp = 2,9-dimethyl-1,10-phenanthroline) dissolved in acetonitrile and dichloromethane. The steady-state photolumi ...

Amer Chemical Soc2013

Nonadiabatic ab initio molecular dynamics using linear-response time-dependent density functional theory

Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Thomas James Penfold

We review our recent work on ab initio nonadiabatic molecular dynamics, based on linear-response timedependent density functional theory for the calculation of the nuclear forces, potential energy surfaces, and nonadiabatic couplings. Furthermore, we descr ...

Versita2013

A wavelet analysis for the X-ray absorption spectra of molecules

Majed Chergui, Ursula Röthlisberger, Ivano Tavernelli, Amal El Nahhas, Marco Eli Reinhard, Thomas James Penfold

We present a Wavelet transform analysis for the X-ray absorption spectra of molecules. In contrast to the traditionally used Fourier transform approach, this analysis yields a 2D correlation plot in both R- and k-space. As a consequence, it is possible to ...

American Institute of Physics2013

Evidence for a Peierls phase-transition in a three-dimensional multiple charge-density waves solid

Majed Chergui, Mathieu Julien Gino Cottet, Fabrizio Carbone, Thomas James Penfold

The effect of dimensionality on materials properties has become strikingly evident with the recent discovery of graphene. Charge ordering phenomena can be induced in one dimension by periodic distortions of a material's crystal structure, termed Peierls or ...

National Academy of Sciences2012

Quantum dynamics study of the competing ultrafast intersystem crossing and internal conversion in the "channel 3" region of benzene

Thomas James Penfold

Time-resolved photoelectron spectroscopy can obtain detailed information about the dynamics of a chemical process on the femtosecond timescale. The resulting signal from such detailed experiments is often difficult to analyze and therefore theoretical calc ...

American Institute of Physics2012

A femtosecond fluorescence study of vibrational relaxation and cooling dynamics of UV dyes

Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo, Thomas James Penfold

We present a femtosecond broad-band fluorescence up-conversion study of the vibrational relaxation dynamics of two UV chromophores, 2,5-diphenyloxazole (PPO) and para-terphenyl (pTP), pumped with a large excess of vibrational energy (>2000 cm(-1)). The ban ...

2012

Ultrafast anisotropic x-ray scattering in the condensed phase

Majed Chergui, Ursula Röthlisberger, Ivano Tavernelli, Thomas James Penfold

The advent of x-ray free electron lasers offers new opportunities for x-ray scattering (XRS) studies of ultrafast molecular dynamics in liquids, which have so far been limited to the 100 ps resolution of synchrotrons. In particular, anisotropic XRS induced ...

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2012

Simulations of X-ray absorption spectra: the effect of the solvent

Majed Chergui, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Thomas James Penfold

We perform quantum mechanics/molecular mechanics molecular dynamics simulations on the Pt-2(P2O5H2)(4) (abbreviated PtPOP) complex; in water, dimethylformamide and ethanol. These are used to calculate the ground state X-ray absorption spectrum of the ...

2012

Ultrafast X-ray Absorption Studies of the Structural Dynamics of Molecular and Biological Systems in Solution

Majed Chergui, Frank van Mourik, Van Thai Pham, Renske Marjan van der Veen, Frederico Alves Lima, Marco Eli Reinhard, Mercedes Hannelore Rittmann-Frank, Thomas James Penfold, Lotta Susanne Karlsson

We review our recent studies of excited state structures and dynamics of chemical and biological systems with pico- and femtosecond X-ray absorption spectroscopy in the liquid phase. ...

2011

Mixed Quantum Mechanical/Molecular Mechanical (QM/MM) simulations of Adiabatic and Nonadiabatic Ultrafast Phenomena

Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Marilisa Neri, Pablo Campomanes Ramos, Stefano Vanni, Andrey Laktionov, Thomas James Penfold

A thorough theoretical description of ultrafast phenomena that occur in complex systems constitutes a formidable challenge. It not only necessitates the use of quantum mechanical methods that can describe ground and possibly even electronically excited sta ...

Schweizerische Chemische Gesellschaft2011

Local control theory in trajectory-based nonadiabatic dynamics

Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Thomas James Penfold

In this paper, we extend the implementation of nonadiabatic molecular dynamics within the framework of time-dependent density-functional theory in an external field described in Tavernelli et al. [Phys. Rev. A 81, 052508 (2010)] by calculating on-the-fly p ...

2011

Pushing the Frontiers of First-Principles Based Computer Simulations of Chemical and Biological Systems

Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Marilisa Neri, Pablo Campomanes Ramos, Stefano Vanni, Elizabeth Claire Brunk, Manuel Dömer, Andrey Laktionov, Negar Ashari Astani, Polydefkis Diamantis, Thomas James Penfold, Giulia Palermo

The Laboratory of Computational Chemistry and Biochemistry is active in the development and application of first-principles based simulations of complex chemical and biochemical phenomena. Here, we review some of our recent efforts in extending these metho ...

2011

Probing the Transition from Hydrophilic to Hydrophobic Solvation with Atomic Scale Resolution

Majed Chergui, Paul Beaud, Ivano Tavernelli, Amal El Nahhas, Van Thai Pham, Renske Marjan van der Veen, Frederico Alves Lima, Thomas James Penfold

Picosecond and femtosecond X-ray absorption spectroscopy is used to probe the changes of the solvent shell structure upon electron abstraction of aqueous iodide using an ultrashort laser pulse. The transient L-1,L-3 edge EXAFS at 50 ps time delay points to ...

2011

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