SEMICLASSICAL MOLECULAR DYNAMICS OF ADIABATIC AND NONADIABATIC PROCESSES
type: CreativeWork
description: Molecular dynamics over the years has been established as a powerful yet sim- ple technique capable of offering new physical insights into molecular processes. Some of the most desirable features are that it retains favorable scalability with the increasing number of degrees of freedom and can also be used to reproduce processes happening on relatively long time scales. On the other hand, since molec- ular dynamics is based on classical mechanics, it neglects the quantum nature of the nuclear motion and will eventually lead to some noticeable deviations from the real behavior of molecular systems. Instead, when considering a quantum picture of the nuclear dynamics all of the previously cited desirable features of molecular dynamics tend to vanish. Making the whole picture usually more complicated and computationally daunting. Semiclassical methods are in part able to conciliate the best features of both worlds, allowing for an intuitive description of the underlying nuclear quantum dynamics based on classical molecular dynamics and at the same time keeping the scalability in function of the system dimensionality favorable. Throughout this thesis, semiclassical methods are employed to compute vibrational and vibronic spectra. More specifically, the first part of the manuscript will be dedi- cated to a quick review of the theory of the semiclassical initial value representation and its application to spectroscopy. The objective of the first Chapter is not only to show the origins of the semiclassical approximation but also to describe some strategies and further approximations that can pave the way for the simulations of molecular systems featuring up to 10000 degrees of freedom. Later, in the same part of the manuscript, it is also explored the idea of including nonadiabatic effects to semiclassical vibrational spectroscopy by employing the Meyer-Miller-Stock-Thoss mapping. In Chapter 3 a simple study case regarding the formaldehyde molecule is used to dig deeper int…
abstract: Molecular dynamics over the years has been established as a powerful yet sim- ple technique capable of offering new physical insights into molecular processes. Some of the most desirable features are that it retains favorable scalability with the increasing number of degrees of freedom and can also be used to reproduce processes happening on relatively long time scales. On the other hand, since molec- ular dynamics is based on classical mechanics, it neglects the quantum nature of the nuclear motion and will eventually lead to some noticeable deviations from the real behavior of molecular systems. Instead, when considering a quantum picture of the nuclear dynamics all of the previously cited desirable features of molecular dynamics tend to vanish. Making the whole picture usually more complicated and computationally daunting. Semiclassical methods are in part able to conciliate the best features of both worlds, allowing for an intuitive description of the underlying nuclear quantum dynamics based on classical molecular dynamics and at the same time keeping the scalability in function of the system dimensionality favorable. Throughout this thesis, semiclassical methods are employed to compute vibrational and vibronic spectra. More specifically, the first part of the manuscript will be dedi- cated to a quick review of the theory of the semiclassical initial value representation and its application to spectroscopy. The objective of the first Chapter is not only to show the origins of the semiclassical approximation but also to describe some strategies and further approximations that can pave the way for the simulations of molecular systems featuring up to 10000 degrees of freedom. Later, in the same part of the manuscript, it is also explored the idea of including nonadiabatic effects to semiclassical vibrational spectroscopy by employing the Meyer-Miller-Stock-Thoss mapping. In Chapter 3 a simple study case regarding the formaldehyde molecule is used to dig deeper int…
author: MOSCATO, DAVIDE
language: eng
keywords: Semiclassical Dynamic, Nonadibatic Dynamic, Theoretical Chemistry, Vibrational Spectroscopy, Vibronic Spectroscopy, Settore CHEM-02/A - Chimica fisica
date published: 2025-02-03
date modified: 2026-07-27T20:19:00Z
provider: Università degli Studi di Milano
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Università degli Studi di Milano

PropertyValue
property ID: Handle
value: https://hdl.handle.net/2434/1135395