Now showing items 1-11 of 11

    • Atomistic Study of Energy Funneling in the Light-Harvesting Complex of Green Sulfur Bacteria 

      Huh, Joonsuk; Saikin, Semion K.; Brookes, Jennifer Clare; Valleau, Stephanie; Fujita, Takatoshi; Aspuru-Guzik, Alan (American Chemical Society (ACS), 2014)
      Phototrophic organisms such as plants, photosynthetic bacteria, and algae use microscopic complexes of pigment molecules to absorb sunlight. Within the light-harvesting complexes, which frequently have several functional ...
    • Atomistic Study of the Long-Lived Quantum Coherences in the Fenna-Matthews-Olson Complex 

      Shim, Sangwoo; Rebentrost, Patrick; Valleau, Stephanie; Aspuru-Guzik, Alan (Biophysical Society, 2011)
      A remarkable amount of theoretical research has been carried out to elucidate the physical origins of the recently observed long-lived quantum coherence in the electronic energy transfer process in biological photosynthetic ...
    • Electromagnetic Study of the Chlorosome Antenna Complex of Chlorobium tepidum 

      Valleau, Stephanie; Saikin, Semion K.; Ansari-Oghol-Beig, Davood; Rostami, Masoud; Mossallaei, Hossein; Aspuru-Guzik, Alan (American Chemical Society (ACS), 2014)
      Green sulfur bacteria is an iconic example of nature’s adaptation: thriving in environments of extremely low photon density, the bacterium ranks itself amongst the most efficient natural lightharvesting organisms. The ...
    • Exciton Transport in Thin-Film Cyanine Dye J-Aggregates 

      Valleau, Stephanie; Saikin, Semion K.; Yung, Man-Hong; Aspuru-Guzik, Alan (American Institute of Physics, 2012)
      We present a theoretical model for the study of exciton dynamics in J-aggregated monolayers of fluorescent dyes. The excitonic evolution is described by a Monte-Carlo wave function approach which allows for a unified ...
    • First Principles Semiclassical Calculations of Vibrational Eigenfunctions 

      Ceotto, Michele; Valleau, Stéphanie; Tantardini, Gian Franco; Aspuru-Guzik, Alán (American Institute of Physics, 2011)
      Vibrational eigenfunctions are calculated on-the-fly using semiclassical methods in conjunction with ab initio density functional theory classical trajectories. Various semiclassical approximations based on the time-dependent ...
    • Influence of Force Fields and Quantum Chemistry Approach on Spectral Densities of BChlain Solution and in FMO Proteins 

      Chandrasekaran, Suryanarayanan; Aghtar, Mortaza; Valleau, Stephanie; Aspuru-Guzik, Alan; Kleinekathöfer, Ulrich (American Chemical Society (ACS), 2015)
      Studies on light-harvesting (LH) systems have attracted much attention after the finding of long-lived quantum coherences in the exciton dynamics of the Fenna–Matthews–Olson (FMO) complex. In this complex, excitation energy ...
    • Machine learning exciton dynamics 

      Hase, Florian; Valleau, Stephanie; Pyzer-Knapp, Edward; Aspuru-Guzik, Alan (Royal Society of Chemistry (RSC), 2016)
      Obtaining the exciton dynamics of large photosynthetic complexes by using mixed quantum mechanics/molecular mechanics (QM/MM) is computationally demanding. We propose a machine learning technique, multi-layer perceptrons, ...
    • On the Alternatives for Bath Correlators and Spectral Densities from Mixed Quantum-Classical Simulations 

      Valleau, Stephanie; Eisfeld, Alexander; Aspuru-Guzik, Alan (American Institute of Physics, 2012)
      We investigate on the procedure of extracting a “spectral density” from mixed QM/MM calculations and employing it in open quantum systems models. In particular, we study the connection between the energy gap correlation ...
    • Parametric Hierarchical Matrix Approach for the Wideband Optical Response of Large-Scale Molecular Aggregates 

      Ansari-Oghol-Beig, Davood; Rostami, Masoud; Chernobrovkina, Ekaterina; Saikin, Semion K.; Valleau, Stephanie; Mosallaei, Hossein; Aspuru-Guzik, Alan (AIP Publishing, 2013)
      Fast and efficient calculations of optical responses using electromagnetic models require computational acceleration and compression techniques. A hierarchical matrix approach is adopted for this purpose. In order to ...
    • Photonics meets excitonics: natural and artificial molecular aggregates 

      Saikin, Semion K.; Eisfeld, Alexander; Valleau, Stephanie; Aspuru-Guzik, Alan (Walter de Gruyter GmbH, 2013)
      Organic molecules store the energy of absorbed light in the form of charge-neutral molecular excitations -- Frenkel excitons. Usually, in amorphous organic materials, excitons are viewed as quasiparticles, localized on ...
    • Theoretical study of exciton transport in natural and synthetic light-harvesting systems 

      Valleau, Stephanie (2016-05-04)
      In the first part of this dissertation, we investigate on the presence of quantum effects in the exciton dynamics of the Fenna-Matthews-Olson photosynthetic complex of green sulfur bacteria using an atomistic Quantum ...