Xin Chen
From WikidChem
Contents |
Research Interests
The Generalized MP/SOFT Methodology
My research interests concern the generalization of the matching pursuit/split operator Fourier transform (MP/SOFT) method, recently developed for propagation of multidimensional wavepackets, to calculations of thermal correlation functions and simulations of nonadiabatic quantum dynamics. The new methods combine a self-consistent iterative scheme for selection of coherent state basis functions from overcomplete basis sets and a greedy algorithm based on successive orthogonal projections of the selected basis functions onto the time-dependent state. The Bloch equation is integrated via imaginary-time propagation of the density matrix, exploiting its analogy with the time-dependent Schr¨odinger equation. The Heisenberg time-evolution operators, involved in the coordinate representations of thermal correlation functions, are analogously evaluated by real-time propagation in dynamically adaptive coherent-state representations.
Our benchmark studies show that the resulting method can provide quantitative descriptions of both quantum coherences and classical dephasing dynamics as well as the effect of temperature on the classical and quantum relaxation time scales. The extension to simulations of nonadiabatic quantum dynamics, implementing the unitary Trotter expansion of the time-evolution operator according to a nonperturbative scheme, offers significant advantages relative to earlier developments based on the first order Dyson expansion. Applications to studies of quantum reaction dynamics in polyatomic systems include the photophysics of pyrazine, described by the relaxation of 24-dimensional wavepacketes at a conical intersection of coupled excited state potential energy surfaces and the photoisomerization of the retinal chromophore visual in rhodopsin modeled by 25-dimensional wavepackets evolving on electronically coupled potential energy surfaces.
[edit]Publications
J. Chem. Phys., 122, 64102, 2005
Matching-Pursuit Split Operator Fourier Transform Computations of Thermal Correlation Functions, by Xin Chen, Yinghua Wu and Victor S. Batista.
J. Chem. Phys., 125, 124313, 2006
Matching-Pursuit Split Operator Fourier Transform Simulations of Excited-State Nonadiabatic Quantum Dynamics in Pyrazine, by Xin Chen and Victor S. Batista.
Photochem. Photobiol., 190, 274-282, 2007
The MP/SOFT Methodology for Simulations of Quantum Dynamics: Model Simulations of the Photoisomerization of the Retinyl Chromophore in Rhodopsin, by Xin Chen and Victor S. Batista.
[edit]Presentations
Poster Presented at the 2007 CECAM Workshop on Chemical Dynamics, Dublin, Ireland
The future work: Fixed Points and Root Search of Nonlinear differential equations in the application of Quantum Dynamics.
Probability, Mathematical Physics and Mathematical problem in physics and chemistry.
[edit]Mathematics, Physics and Mathematics
My friend, Prof. Yan Alexander Wang at University of British Columbia has a very intersting collection of articles about science, http://www.chem.ubc.ca/faculty/wang/wisdom/ .
[edit]Hobbies
Basketball
