Calculation of Time Correlation Functions and Rate Constants in LiquidSolutions.

Nonequlibrium Statistical Mechanics;Vibrational Energy Relaxation;Quantum Dynamics;Diffusion;Reaction Kinetics;Chemistry;Science;Chemistry

Vazquez, Francisco XavierSension, Roseanne J. ;

University of Michigan

关键词: Nonequlibrium Statistical Mechanics;    Vibrational Energy Relaxation;    Quantum Dynamics;    Diffusion;    Reaction Kinetics;    Chemistry;    Science;    Chemistry;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/78802/fxv_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

In this thesis, we have used the time correlation formalism (TCF) to calculatethe rates of dynamic processes in liquid solutions. This formalism allows us to cal-culate of dynamic properties with time scales that are usually inaccessible to normalmolecular dynamics simulations. Within this framework we have studied vibrationalenergy relaxation (VER), di¤usion, and isomerization reaction kinetics. We have de-veloped an extension to the previously derived linearized semiclassical local harmonicapproximation (LSC-LHA) that eliminates the need to calculate di¢ cult derivativesof the forces. This method was applied to VER in nonpolar solvents and foundto agree well with experiment. We then applied the new method to the problem ofVER in polar solvents. We found that the classical electrostriction explanation of theenhanced VER rate in polar solvents does not hold if quantum mechanical e¤ectsplay an signi cant role. We also derived another extension to the LSC-LHA thateliminates a major computational bottleneck involving a normal mode analysis thatmust be preformed for every trajectory. This new method was applied to the calcu-lation of di¤usion coe¢ cients in quantum liquids and was found to agree well withexperimental results, but also overestimated the imaginary part of the TCF (whichis purely quantum mechanical) greatly. Lastly we used a linear response approach tomodel the isomerization of hexatriene in methanol and cyclohexane. We found thatwe were able to qualitatively predict experimental trends and were able to create amicroscopic model from our simulations to explain the experimental results.