Brown, Alexander - University of Alberta

研究领域

Theoretical/computational studies of molecular photochemistry and laser control The interaction of light (naturally occurring or from lasers) with molecules can induce a variety of dynamical processes including electronic excitation, structural change, dissociation, and vibration. Recently, it has become possible to tailor laser fields to actively manipulate these dynamical processes. We look to develop and utilize both electronic structure and dynamical methods to understand molecular photochemistry and to manipulate molecular processes. Optimal control theory for laser control: The use of tailored laser pulses to control chemical processes has received much attention recently, in part due to the rapid development of experimental pulse shaping techniques. We are using optimal control theory (OCT) to determine the tailored laser pulses needed to achieve control. In order to treat laser control for polyatomic molecules with more than a few (3-6) degrees of freedom, we are developing the use of the Multi-Configurational-Time-Dependent-Hartree (MCTDH) method for solving the time-dependent Schrödinger equation of the involved states in combination with OCT. In related work, we are examining the use of genetic algorithms to determine the optimal laser fields for control. The initial focus is on the study of molecular quantum computing where vibrational states represent the quantum bits (qubits) and tailored laser fields are used for implementing quantum gate operations. Molecular photodissociation dynamics: Molecular photofragmentation often involves multiple electronically excited states and non-adiabatic transitions between these states may occur as the molecule dissociates. Our understanding of the dissociation dynamics requires both high-level theoretical calculations and the measurement of a variety of observables, particularly angular momentum distributions. We are interested in determining the complete angular momentum distributions and vector correlation coefficients (alignment and orientation) for atomic fragments resulting from molecular photofragmentation. We are also interested in developing general purpose direct dynamics (ab initio molecular dynamics) software for the study of molecular photodissociation/photochemistry of polyatomic molecules for which quantum dynamics calculations are not feasible. Photochemistry of fluorescent proteins: Fluorescent proteins derived from Aequorea victoria jellyfish green fluorescent protein (GFP) are widely used in cell and molecular biology as fluorescent labels and reporter molecules. Protein engineering allows creating a number of fluorescent proteins with various photophysical properties by changing the structure of the chromophore and/or protein environment around the chromophore. We are interested in computational modeling of the photochemical processes in fluorescent proteins to gain mechanistic insights necessary to improve and extend their utility in molecular biology.

近期论文

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Probing Ground and Low-Lying Excited States for HIO2 Isomers G.L.C. de Souza and A. Brown J. Chem. Phys. 141, 234303 (2014) Two-photon absorption in fluorescent protein chromophores: TDDFT and CC2 results M. Salem and A. Brown J. Chem. Theo. Comp. 10 3260-3269 (2014). Accessing Zinc Monohydride Cations via Coordinative Interactions P.A. Lummis, M.R. Momeni, M.W. Lui, R. McDonald, M.J. Ferguson, M. Miskolzie, A. Brown and E. Rivard Angewandte Chemie International Edition 53 9347-9351 (2014). Simulation of the Resonance Raman Spectrum For Uracil S. Sun and A. Brown J. Phys. Chem. A 118 9228-9238 (2014). Coaxing Solid State Phosphorescence from Tellurophenes G.He, W.Torres Delgado, D.J.Schatz, C.Merten, A.Mohammadpour, L.Mayr, M.J. Ferguson, R. McDonald, A. Brown, K. Shankar and E. Rivard Angewandte Chemie International Edition 53 4587-4591 (2014). Carbene-bound Borane and Silane Adducts: A Comprehensive DFT Study on their Stability and Propensity for Hydride-mediated Ring Expansion M. R. Momeni, E. Rivard and A. Brown Organometallics 32 6201-6208 (2013). Hyperfine Constants for Aluminum Hydride and Aluminum Deuteride A. Brown and R.E. Wasylishen J. Mol. Spectrosc. 292 8--14 (2013). Stable Complexes of Parent Digermene: an Inorganic Analogue of Ethylene S. M. Ibrahim Al-Rafia, M. R. Momeni, M. J. Ferguson, R. McDonald, A. Brown and E. Rivard Organometallics. 32 6658-6665 (2013). Controlled Growth of Dichlorogermanium Oligomers from Lewis Basic Hosts S. M. Ibrahim Al-Rafia, M. R. Momeni, R. McDonald, M. J. Ferguson, A. Brown and E. Rivard Angewandte Chemie 52 6390-6395 (2013). (VIP article) Computational Study of the Excited State Properties of Modified RNA Nucleobases M. Gedik and A. Brown J. Photochem. and Photobiol. A. 259 25-32 (2013). Ab Initio Potential Energy and Dipole Moment Surfaces for CS2: Determination of Molecular Vibrational Energies E. Pradhan, J.-L. Carreon-Macedo, J.E. Cuervo, M. Schroeder, and A. Brown J. Phys. Chem. A 117 6925-6931 (2013). [Joel M. Bowman Festschrift] The vibrationally mediated photodissociation of Cl2 E.K. Campbell, A.B. Alekseyev, G.G. Balint-Kurti, M. Brouard, A. Brown, R.J. Buenker, A.J. Johnsen, D.B. Kokh, S. Lucas, and B. Winter J. Chem. Phys. 137 124310 (2012). Nuclear quadrupole coupling constants for N2O: Experiment and Theory A. Brown and R.E. Wasylishen J. Phys. Chem. A, 116 9769-9776 (2012) Effect of Laser Pulse Shaping Parameters on the Fidelity of Quantum Logic Gates R.R. Zaari and A. Brown J. Chem. Phys. 137 104306 (2012). Electronic polarization effects in the photodissociation of Cl2 E.K. Campbell, A.B. Alekseyev, G.G. Balint-Kurti, M. Brouard, A. Brown, R.J. Buenker, R. Cireasa, A.J. Gilchrist, A.J. Johnsen, D.B. Kokh, S. Lucas, G.A.D. Ritchie, T.R. Sharples, and B. Winter J. Chem. Phys. 136 164311 (2012). A complete quantum mechanical study of chlorine dissociation A.J. Johnsen, A.B. Alekseyev, G.G. Balint Kurti, M. Brouard, A. Brown, R.J. Buenker, E.K. Campbell, and D.B. Kokh J. Chem. Phys. 136 164310 (2012). Deuterium Kinetic Isotope Effects on the Dissociation of a Protein-Fatty Acid Complex in the Gas Phase L. Liu, K. Michelsen, E. Kitova, P. Schnier, A. Brown, J. Klassen J. Am. Chem. Soc. 134 5931-5937 (2012). Substituted benzoxadiazoles as fluorogenic probes: A computational study of absorption and emission A. Brown, T.Y. Ngai, M.A. Barnes, J.A. Key and C.W. Cairo J. Phys. Chem. A 116 46-54 (2012). Effect of diatomic molecular properties on binary laser pulse optimizations of quantum gate operations R.R. Zaari and A. Brown J. Chem. Phys., 135 044317 (2011). Determination of molecular vibrational energies using the ab initio semiclassical initial value representation: Application to formaldehyde S.Y.Y. Wong, D. Benoit, M. Lewerenz, A. Brown and P.-N. Roy J. Chem. Phys., 134 094110 (2011).