Download or read book Nonequilibrium Effects of Vibrational Strong Coupling on Chemical Reactions written by Matthew Du and published by . This book was released on 2022 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: An ongoing goal in chemistry is to develop cheaper and greener methods of catalysis. Recent experiments show modified reaction kinetics when placing molecules inside an optical cavity and achieving vibrational strong coupling (VSC). VSC occurs when N - 1 molecular vibrations strongly interact with a cavity photon mode to form two hybrid light-matter modes called polaritons, as well as N - 1 optically dark vibrational modes. Since the aforementioned changes in reactivity occur without external pumping, VSC holds promise as a future tool in industrial catalysis. However, VSC-modified chemistry is not well understood. Initial theoretical efforts demonstrate that transition-state theory (TST), the most commonly used reaction-rate theory, predicts negligible changes in reaction rate due to VSC for typical experimental conditions. Subsequent works have begun to consider how VSC influences reactions for which the assumptions of TST break down. In this dissertation, we theoretically explore how VSC affects reactions where thermalization occurs on a similar or longer time scale compared to reactive events. Such reactions, which include photochemical processes, can violate the TST assumption that internal thermal equilibrium is maintained throughout the reaction. First, we study thermally activated electron transfer. For two molecules under VSC, we find that thermalization can be accelerated by cavity decay, a dissipative channel available to polaritons but not the uncoupled molecular vibrations. As a result, nonequilibrium effects that impact the reaction rate are suppressed. For a disordered ensemble of many molecules, VSC yields dark modes that are delocalized across several molecules. We reveal an unconventional mechanism by which this delocalization suppresses reactive events but not vibrational decay, thus speeding up the reaction. We then investigate photochemistry under VSC. Specifically, we propose a "remote control" of chemistry, where photoexcitation of molecules in one optical cavity enhances the photoisomerization of molecules in another optical cavity. This idea challenges the standard paradigm that a catalyst must bind its substrate to change reactivity. Finally, we develop a comprehensive theory for a related phenomenon: polariton-assisted energy transfer between spatially separated molecules. This theory not only sheds light on experimental observations but even predicts a number of intriguing effects, including the role reversal of donor and acceptor chromophores.

Download or read book Effects of Vibrational Strong Coupling on Ground state Chemical Kinetics written by Jorge Arturo Campos Gonzalez Angulo and published by . This book was released on 2021 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The energy of an electromagnetic field can be stored with the help of confining devices, known as optical cavities, that localize it temporarily. If a dielectric material with a high dipole moment shares space with the confined field, the optical properties of the system correspond to neither of its components but rather to a light-matter hybrid, whose excitations are called polaritons. While experimental realizations of this phenomenon date back to decades ago, it was not until the last decade when advances in sample preparation technologies enabled the investigation of the consequences of polariton formation on the observables related to the material. In this regard, a particularly active area of interest is the study of chemical reactivity under strong-light matter coupling. A striking development in the area is the observation that reactions inside infrared cavities, which couple to bond vibrations, experience a change in their rate even without any energy source other than room temperature. This effect has been observed in various reactions, including organometallic and carbonyl substitutions, and even in enzymatic processes. Consistently, these experiments show that rate modification is subject to the same conditions as polariton formation: the requirement of resonance between cavity and vibration and the intensification of the effect with the concentration of the sample. However, cavity quantum electrodynamics (CQED), the same theory that has successfully explained and predicted the optical properties of polaritons for decades, at first glance suggests that a local process such as a chemical reaction should not be affected by an essentially delocalized phenomenon such as light-matter coupling.This dissertation presents how CQED combines with two approaches to chemical rate theory: adiabatic reactions described within transition state theory (TST), and non-adiabatic processes, described by Marcus' theory of charge transfer. In the first case, it is found that under typical experimental conditions, a description at the level of TST predicts that vibrational strong light-matter coupling should produce no effect on the chemical rate. In contrast, for non-adiabatic processes, it is possible to conceptualize rate alteration in terms of a modified distribution of activation energies that accounts for the presence of polariton modes. Additionally, this work presents a group-theoretical method to simplify the description of a collective of identical oscillators with an arbitrary structure to a cavity mode, which may have applications to understanding chemical processes and non-linear response phenomena.

Download or read book Nonequilibrium Vibrational Kinetics written by Mario Capitelli and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is devoted to the systematic treatment of nonequi 1 ibrium vibrational kinetics in molecular systems. Particular emphasis is given to the vibrational excitation of diatomic molecules by low-energy electrons in a discharge and by IR photons in laser-pumped systems. The book follows the different steps of the introduction, redistribution, loss, and chemical conversion of the vibrational quanta, from the points of view of the overall kinetics and the dynamics of elementary processes. These two aspects are balanced in a multidisciplinary approach. The different chapters give the basic instruments (theoretical and experimental) which are needed to understand the ki netics of nonequilibrium systems. The book will introduce the reader to different areas such as plasmachemistry, laser chemistry, IR and Raman spectroscopy, and relaxation phenomena, emphasizing how the vibrational energy affects such research fields. The chapters dedicated to collisional dynamics involving vibrational excited molecules provide an introduc tion to the modern techniques uti 1 ized in the scattering theory of inelastic and reactive collisions. The extension of the vibrational kinetics to polyatomic mole cules, discussed in Chap. 10, is the natural bridge between coll ision and coll i sionless regimes. In conclusion, we hope that the approach followed in this book will stimulate the collaboration of researchers coming from different research fields, which are too often completely separate.

Download or read book Polariton Chemistry written by Joel Yuen-Zhou and published by . This book was released on 2023-05-09 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a pedagogical introduction to the emerging field of Polariton Chemistry, where optical cavities are utilized to control the physicochemical properties and dynamics of molecular systems. Given the early stages of this interdisciplinary research area, it is important to provide a common language and starting point for interested researchers across Chemistry, Physics, and Engineering This edited compendium fills a void given that there is currently no analogue in the current literature. Topics covered include Single-Molecule Strong Light-Matter Coupling; Collective Strong Light-Matter Coupling; and Ultrastrong Light-Matter Coupling

Download or read book Reproducibility of Effects of Vibrational Strong Coupling on Chemical Reaction Rates written by Garret Douglas Wiesehan and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to conduct new chemical reactions, or to control known reactions in new ways, is a key area of academic and societal interest. In recent years, developments in the field of photonics have revealed phenomena that occur when molecules strongly interact with light. One area of interest is in vibrational strong coupling, which occurs when molecular bond vibrations strongly interact with electromagnetic fields in the mid-infrared regime. In a fascinating series of experiments, reactions were performed under vibrational strong coupling and observed to be dramatically modified. Given the impact that these findings imply, independent verification and a thorough understanding of the underlying mechanisms is critical. One such reaction, where the ester para-nitrophenyl acetate is hydrolyzed by tetrabutylammonium fluoride in ethyl acetate, reportedly accelerated by an order of magnitude. An attempt to reproduce these findings with the goal of further investigating the mechanism of reaction modification is presented. While experimental procedures and conditions were performed closely to those of the original work, no reaction modification was observed. Furthermore, no significant change in reaction rate with detuning was found. An analysis of the reaction system was performed using Jaynes-Cummings coupled oscillator and transfer matrix method models to confirm vibrational strong coupling and investigate the lack of observed reaction modification. The potential of vibrational strong coupling as new tool for reaction control is tantalizing and may usher in a new era of chemical synthesis, however a robust understanding of the underlying mechanisms involved are crucial to its realization.

Download or read book Impact of Vibrational Strong Coupling on Chemistry and Molecular Photophysics written by Mario Vincenzo Imperatore and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecules are thought to interact resonantly with the confined field of a properly designed structure to access hybrid light-matter states, the so-called polaritons. These have unique properties because they inherit both the characteristics of light and matter. Weak and strong coupling effects are particularly interesting at infrared wavelengths, since most of the molecular vibrations fall in this range. The work reported in this Dissertation, in particular, focuses on four experiments, each of which aimed at strengthening and improving previous literature results, to conceive a clear contribution to the topic. The Dissertation begins with introductory chapters that explain the purpose of the research and provide an overview of the topic. The following chapter provides a brief overview of the most pertinent physics related to the subject of the dissertation. The four experimental chapters then explore the interaction between infrared light and matter in applications such as chemical reactivity, charge transport, and nonlinear generation. One of these results, in particular, contributed to the broad topic of the reproducibility of cavity catalysis experiments, with a disproof that ignited the attention of other groups and started a debate in the scientific community about the existence of such effects. The research carried out in these years was made possible by the invaluable assistance of other researchers from Penn State and other American universities. Without these collaborations, which are essential to scientific exploration, many of these experiments would not have been carried out.

Download or read book Chemical Reactions in Clusters written by Elliot R. Bernstein and published by Oxford University Press. This book was released on 1996-06-06 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers important new developments of the last five years in the area of cluster chemistry, presenting an excellent view of the successes and shortcomings of both current state-of-the-art theory and experiment. Each chapter, contributed by a leading expert, places heavy emphasis on theory without which the detailed analysis of the spectroscopic and kinetic results would be compromised. The cluster reactions reviewed in this work include electron and proton transfer reactions, hot atom reactions, vibrational predissociation, radical reactions, and ionic reactions. Some of the theories applied throughout the text are product state distribution determinations, state-to-state dynamical information, and access to the transition stage of the reaction. The discussions serve as a benchmark of how far the field has come since the mid 1980's and will be a good update for students and researchers interested in this area of physical chemistry.

Download or read book Polaritonic Chemistry written by Javier Galego Pascual​ and published by Springer Nature. This book was released on 2020-06-25 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polaritonic chemistry is an emergent interdisciplinary field in which the strong interaction of organic molecules with confined electromagnetic field modes is exploited in order to manipulate the chemical structure and reactions of the system. In the regime of strong light-matter coupling the interaction with the electromagnetic vacuum obliges us to redefine the concept of a molecule and consider the hybrid system as a whole. This thesis builds on the foundations of chemistry and quantum electrodynamics in order to provide a theoretical framework to describe these organic light-matter hybrids. By fully embracing the structural complexity of molecules, this theory allows us to employ long-established quantum chemistry methods to understand polaritonic chemistry. This leads to predictions of substantial structural changes in organic molecules and the possibility of significantly influencing chemical reactions both in the excited and ground states of the system.

Download or read book NASA Technical Note written by and published by . This book was released on 1972 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Jahn Teller Effect and Vibronic Interactions in Modern Chemistry written by Isaac Bersuker and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first half of the title of this book may delude the uninitiated reader. The term '"Jahn-Teller effect," taken literally, refers to a special effect inherent in particular molecular systems. Actually, this term implies a new approach to the general problem of correlations between the structure and properties of any molecular polyatomic system, including solids. Just such a new approach, or concept (in some sense, a new outlook or even a new way of thinking), which leads not to one special effect but to a series of different effects and laws, is embodied in the many ( ~ 4000) studies devoted to the investigation and application of the Jahn-Teller effect. The term "vibronic interactions" seems to be most appropriate to the new concept, and this explains the origin of the second half of the title. The primary objective of this book is to present a systematic develop ment of the concept of vibronic interactions and its applications, and to illustrate its possibilities and significance in modern chemistry. In the first three chapters (covering about one-third of the book) the theoretical background of the vibronic concept and Jahn-Teller effect is given. The basic ideas are illustrated fully, although a comprehensive presentation of the theory with all related mathematical deductions is beyond the scope of this book. In the last three chapters the applications of theory to spectro scopy, stereochemistry and crystal chemistry, reactivity, and catalysis, are illustrated by a series of effects and laws.

Download or read book Reaction Rate Theory and Rare Events written by Baron Peters and published by Elsevier. This book was released on 2017-03-22 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reaction Rate Theory and Rare Events bridges the historical gap between these subjects because the increasingly multidisciplinary nature of scientific research often requires an understanding of both reaction rate theory and the theory of other rare events. The book discusses collision theory, transition state theory, RRKM theory, catalysis, diffusion limited kinetics, mean first passage times, Kramers theory, Grote-Hynes theory, transition path theory, non-adiabatic reactions, electron transfer, and topics from reaction network analysis. It is an essential reference for students, professors and scientists who use reaction rate theory or the theory of rare events. In addition, the book discusses transition state search algorithms, tunneling corrections, transmission coefficients, microkinetic models, kinetic Monte Carlo, transition path sampling, and importance sampling methods. The unified treatment in this book explains why chemical reactions and other rare events, while having many common theoretical foundations, often require very different computational modeling strategies. Offers an integrated approach to all simulation theories and reaction network analysis, a unique approach not found elsewhere Gives algorithms in pseudocode for using molecular simulation and computational chemistry methods in studies of rare events Uses graphics and explicit examples to explain concepts Includes problem sets developed and tested in a course range from pen-and-paper theoretical problems, to computational exercises

Download or read book NASA Technical Report written by and published by . This book was released on 1969 with total page 1158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Ambient Vibrational Nonequilibrium on the Propagation of Acoustic gravity Waves written by Jayaraman Srinivasan and published by . This book was released on 1974 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is a theoretical study of the effect of ambient vibrational nonequilibrium(vibrational or radiative) on the propagation of acoustic and gravity waves in a gas. In the propagation of such waves, nonequilibrium phenomena can manifest themselves in two distinct ways. This follows from the fact that nonequilibrium can exist in either(or both) the ambient and perturbed states of the gas. It is well known that perturbation nonequilibrium always contribute to damping of the waves. The lesser known effects of ambient nonequilibrium are examined here from the point of view of macroscopic gas dynamics. The physical insight obtained in a one-dimensional analysis is applied to the study of the probable effect of vibrational nonequilibrium(ambient and perturbation) on the propagation of acoustic-gravity waves in Earth's upper atmosphere.

Download or read book Computational and Experimental Study of Nonequilibrium Chemistry in Hypersonic Flows written by Joseph Olejniczak and published by . This book was released on 1997 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical Kinetics written by Vivek Patel and published by BoD – Books on Demand. This book was released on 2012-02-29 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical Kinetics relates to the rates of chemical reactions and factors such as concentration and temperature, which affects the rates of chemical reactions. Such studies are important in providing essential evidence as to the mechanisms of chemical processes. The book is designed to help the reader, particularly students and researchers of physical science, understand the chemical kinetics mechanics and chemical reactions. The selection of topics addressed and the examples, tables and graphs used to illustrate them are governed, to a large extent, by the fact that this book is aimed primarily at physical science (mainly chemistry) technologists. Undoubtedly, this book contains "must read" materials for students, engineers, and researchers working in the chemistry and chemical kinetics area. This book provides valuable insight into the mechanisms and chemical reactions. It is written in concise, self-explanatory and informative manner by a world class scientists in the field.

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Simplified Molecular Model for Studying Vibration dissociation Coupling in Fluid Flows written by Walter Albert Reinhardt and published by . This book was released on 1969 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simplified mathematical model is derived that is useful for studying the effects of vibration-dissociation coupling in fluid flows. The derivation is based on energy-moment procedure for simplifying the master equations. To obtain the model equations it is assumed that the vibrational energy can be approximated by the introduction of two vibrational temperatures. The effects of molecular anharmonicity are also accounted for in an approximate manner. The parameters contained within the equations are evaluated by making comparisons with experimental data. It is shown that the model contains the minimum required structure allowing favorable agreement with existing experimental data. Numerical solutions are given for the quasi-steady zone behind a normal shock wave, for the complete structure of a shock wave, and for nozzle flow. The results provide the appropriate pre-exponential temperature dependence of the effective dissociation rate, yield and induction time before dissociation is observed, and, in the case of expanding flow, yield one-fourth less effective relaxation time than the Landau-Teller theory. The thermodynamic quantities for the vibrational mode (partition function, internal energy, and specific heat) agree accurately with like quantities evaluated from spectroscopic data. By the introduction of appropriate assumptions it is shown that the equations reduce to a form identical to the Marrone-Treanor model except for a "truncation factor". When the vibrational temperatures are not large, the model is identical to that of Landau and Teller. The numerical procedure used to integrate the system of rate and flow equations is also described.