Dumont, Randy - McMaster University - Department of Chemistry & Chemical Biology

个人简介

B.Sc. (University of Western Ontario) Ph.D. (University of Toronto)

研究领域

Current research concerns the simulation of electron transport across a molecule attached to metallic "leads" - i.e. a molecular electronic device (MED). Typically, molecules with an extended p system are connected to gold leads via thiol substituents. MED systems exhibit quantum interference effects that can be exploited (in principle) to construct transistor or diode devices that operate with quantum coherence preserved. Recent work employs the source-sink potential method of Goyer, Ernzerhof and Zhuang [J. Chem. Phys. 126, 144104 (2007)] to model molecular electronic devices. In particular, the approach has been extended to systems with more than one incoming and/or outgoing channel [J. Chem. Phys. 134, 044119 (2011)]. Notable results include the demonstration that degenerate orbitals split into interfering, overlapping resonances when the molecule is attached to leads. Most recently, current-voltage relationships have been investigated, accounting for polarization of the molecule resulting from different lead potentials. Whereas, at the lowest level approximation, the charge on an atom is identified with the square of the atomic orbital coefficient in LUMO (the lowest unoccupied orbital), simulations indicated that the charge is better modeled by the absolute value of the atomic orbital coefficient. This results because the perturbation of the occupied orbitals reduces electron densities where the charges are highest. The result is a more uniform charge distribution than predicted at lowest order. Other recent research is in collaboration with L. Wang and J.M. Dickson. Water flow through a carbon nanotube pore in a graphene-coated membrane has been simulated using non-equilibrium molecular dynamics. Water flow is driven by a pressure difference across the membrane. Conditions are kept consistent with nanofiltration systems currently used for water purification. Carbon -nanotube-based membranes are of great current interest as early results show very high flow rates and excellent filtration characteristics.

近期论文

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R.S. Dumont & P.E. Lock, "Chemistry Review Manual, 2nd Ed." (2012) L. Wang, R.S. Dumont & J.M. Dickson, "Comparison of Two NEMD Simulation Systems for the Pressure-driven Water Permeation through Carbon Nanotube Membranes" (submitted to Microfluidics and Nanofluidics) L. Wang, R.S. Dumont & J.M. Dickson, "Nonequilibrium Molecular Dynamics Simulation of Water Transport through Carbon Nanotube Membranes" J. Chem. Phys. 137, 044102 (2012) PDF J.W. Tromp & R.S. Dumont, "The thermal flux-flux correlation function and classical-quantum correspondence" Mol. Phys. 110, 817-824 (2012) PDF R.S. Dumont, "Two channel conduction through polyacenes - extension of the source-sink potential method to multichannel coupling to leads" J. Chem. Phys. 134, 044119 (2011) PDF R.S. Dumont, "Student Solutions Manual" for use with "Chemistry: Human Activity, Chemical Reactivity" by Mahaffy, Bucat, Tasker, Kotz, Treichel, Weaver and McMurry (2010) R. Rajaie Khorasani & R.S. Dumont, "Implicit restart Lanczos as an eigensolver", Phys. Rev. E 79, 036708 (2009) PDF R. Rajaie Khorasani & R.S. Dumont, "Nonnormal Lanczos methods for quantum scattering", J. Chem. Phys. 129, 034110 (2008) PDF R.S. Dumont & S.W.K. Lam, "Shift equations iteration solution to n-level close coupled equations, and the two-level nonadiabatic tunneling problem revisited", Theor. Chem. Acc. 119, 383-405 (2008) PDF R. Rajaie Khorasani & R.S. Dumont, "Long time wave packet dynamics from energy eigenfunctions; nonuniform energy resolution via adaptive bisection fast Fourier transformation ", J. Chem. Phys. 127, 184107 (2007) PDF J. Sakhr, R.S. Dumont & N.D. Whelan, "Periodic orbit quantization of a weakly interacting two-body system using perturbed symmetry-broken trace formulas", Phys. Rev. A 74, 052104 (2006) PDF R.S. Dumont, Book review: "The quantum classical theory" by G.D. Billing, J. Am Chem. Soc. 126, 7153 (2004) R.S. Dumont, "Flux projections onto channel-specific transit time eigenspaces", J. Mol. Struct. 591, 267–276 (2002) PDF R.S. Dumont, "Time distributions for classically unallowed processes of a 2-level system: nonadiabatic tunneling and above-barrier reflection", J. Chem. Phys. 116, 9158 (2002) PDF H. Kampermann, A.D. Bain & R.S. Dumont, "Residual dipolar coupling in the CP/MAS NMR spectra of spin-1/2 nuclei coupled to quadrupolar nuclei. Application of Floquet theory", J. Chem. Phys.116, 2464-2471 (2002) PDF A.D. Bain & R.S. Dumont, “The concept of quantization in the magnetic resonance of quadrupolar nuclei”, Can. J. Anal. Sci. & Spec. 46, 176-181 (2001) A.D. Bain & R.S. Dumont, "Introduction to Floquet theory. The calculation of spinning sideband intensities in MAS NMR", Concepts Magn. Reson. 13, 159-170 (2001) PDF R.S. Dumont & R. Assalone, "Fast simulation of dynamic two dimensional NMR spectra for systems with many spins or exchange sites ", J. Chem. Phys. 113, 4505-4514 (2000) PDF P. Hazendonk, A.D. Bain, H. Grondey, P.H.M. Harrison & R.S. Dumont, "Floquet theory simulation of exchange lineshapes in CP/MAS NMR spectra", J. Magn. Reson. 146, 33-42 (2000) PDF R.S. Dumont, P. Hazendonk & A.D. Bain, "Dual Lanczos simulation of dynamic NMR spectra for systems with many spins or exchange sites", J. Chem. Phys. 113, 3270-3281 (2000) PDF