Electronic systems condensed-phase

Condensed-phase Electronic Systems Path Integral Simulations... 

CONDENSED-PHASE ELECTRONIC SYSTEMS PATH INTEGRAL SIMULATIONS 475... 

CONDENSED-PHASE ELECTRONIC SYSTEMS. PATH INTEGRAL SIMULATIONS 477... 

This article offers a brief overview of applications of path integral simulations to various aspects of condensed-phase electronic systems. Despite the success of some of the methods described here, many challenges remain for path integral simulations. In particular, a general solution to the sign problem in fermion and real-time problems is of fundamental importance, and such a general method has yet to be found. This search will no doubt dominate research activities in the field of path integral simulations for the next few years. 

Condensed-phase Electronic Systems Path Integral Simulations Monte Carlo Quantum Methods for Electronic Structure Rates of Chemical Reactions Wave Packets. 

The third part of this text focuses on several important dynamical processes in condensed phase molecular systems. These are vibrational relaxation (Chapter 13), Chemical reactions in the barrier controlled and diffusion controlled regimes (Chapter 14), solvation dynamics in dielectric environments (Chapter 15), electron transfer in bulk (Chapter 16), and interfacial (Chapter 17) systems and spectroscopy (Chapter 18). These subjects pertain to theoretical and experimental developments of the last half century some such as single molecule spectroscopy and molecular conduction—of the last decade. 

In condensed-phase molecular systems, and particularly insulating molecular crystals, infrared and Raman spectroscopies are well-established tools for investigating molecular and crystalline structural properties. On the other hand, in inorganic semiconductors and metals the same spectroscopic methods are widely used to evaluate electronic band structure parameters. Organic charge transfer (CT) crystals, as molecular conductors and semiconductors, share some properties of both the above classes of solids, and, therefore, new spectroscopic phenomena are expected, and indeed observed for these materials. ... 

Of course, condensed phases also exliibit interesting physical properties such as electronic, magnetic, and mechanical phenomena that are not observed in the gas or liquid phase. Conductivity issues are generally not studied in isolated molecular species, but are actively examined in solids. Recent work in solids has focused on dramatic conductivity changes in superconducting solids. Superconducting solids have resistivities that are identically zero below some transition temperature [1, 9, 10]. These systems caimot be characterized by interactions over a few atomic species. Rather, the phenomenon involves a collective mode characterized by a phase representative of the entire solid. 

While the classical approach to simulation of slow activated events, as described above, has received extensive attention in the literature and the methods are in general well established, the methods for quantum-dynamical simulation of reactive processes in complex systems in the condensed phase are still under development. We briefly consider electron and proton quantum dynamics. 

Section 3 deals with reactions in which at least one of the reactants is an inorganic compound. Many of the processes considered also involve organic compounds, but autocatalytic oxidations and flames, polymerisation and reactions of metals themselves and of certain unstable ionic species, e.g. the solvated electron, are discussed in later sections. Where appropriate, the effects of low and high energy radiation are considered, as are gas and condensed phase systems but not fully heterogeneous processes or solid reactions. Rate parameters of individual elementary steps, as well as of overall reactions, are given if available. 

The scale of components in complex condensed matter often results in structures having a high surface-area-to-volume ratio. In these systems, interfacial effects can be very important. The interfaces between vapor and condensed phases and between two condensed phases have been well studied over the past four decades. These studies have contributed to technologies from electronic materials and devices, to corrosion passivation, to heterogeneous catalysis. In recent years, the focus has broadened to include the interfaces between vapors, liquids, or solids and self-assembled structures of organic, biological, and polymeric nature. 

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