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A trajectory-based approach to modeling nonlinear infrared spectra : interrogating strong hydrogen bonds and proton transfer

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dc.contributor.advisor Andrei Tokmakoff. en_US Hornng, Andrew D. (Andrew Davis) en_US
dc.contributor.other Massachusetts Institute of Technology. Dept. of Chemistry. en_US 2012-09-27T15:28:34Z 2012-09-27T15:28:34Z 2012 en_US 2012 en_US
dc.description Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2012. en_US
dc.description Cataloged from PDF version of thesis. en_US
dc.description Includes bibliographical references. en_US
dc.description.abstract This work describes a phenomenological approach for modeling linear and nonlinear infrared spectroscopy of condensed phase chemical systems, focusing on applications to strongly hydrogen bonded complexes. To overcome the limitations inherent in common analytical models, I construct full time trajectories for spectroscopic variables, here the vibrational frequencies and transition dipole moments, and use these as inputs to calculate the system response to an applied electric field. This method identifies key dynamical variables, treats these stochastically, and then constructs trajectories of spectroscopic variables from these stochastic quantities through mappings. The correspondence of such fluctuating coordinates and spectroscopic observables is demonstrated for a number of simple cases not adequately addressed using current approximations, including liquid water, strong hydrogen bonds, and proton transfer reactions using ab initio calculations, model potentials, and molecular dynamics. Dynamical information is bestowed upon these trajectories through either a Langevin-like Brownian oscillator model for the bath, full molecular dynamics calculations, or experimentally motivated empirical formulae. Utilizing the semiclassical approximation for the linear and nonlinear response functions, these constructed trajectories give us the ability to numerically calculate nonlinear spectroscopy to examine phenomena previously difficult with other methods, including non-Gaussian dynamics, correlated occurrences, highly anharmonic potentials, and complex system-bath relationships. en_US
dc.description.statementofresponsibility by Andrew D. Horning. en_US
dc.format.extent 151 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri en_US
dc.subject Chemistry. en_US
dc.title A trajectory-based approach to modeling nonlinear infrared spectra : interrogating strong hydrogen bonds and proton transfer en_US
dc.type Thesis en_US S.M. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Chemistry. en_US
dc.identifier.oclc 809934315 en_US

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