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Lecture

Statistical Thermodynamics: Microcanonical and Canonical Ensembles

In course

CH-242(b): Statistical mechanics for chemistry

Ce cours construit la base théorique universelle permettant de comprendre les systèmes à grand nombre de particules. Les méthodes introduites sont utilisées pour éclairer de nombreux phénomènes à travers la chimie. ...

Description

This lecture covers the historical development of kinetic gas theory, Bernoulli's and Maxwell's contributions, the concept of microcanonical ensemble, the definition of macrostate and microstate, and the canonical ensemble. It also discusses the arrangements of N particles in 2 spaces, Stirling's approximation, and the behavior of large and small N values in statistical thermodynamics.

Instructors (2)

Christopher Scott Reilly

Andreas Osterwalder

EDUCATION: 2002: Dr.sc.nat. (ETH Zurich) 1998: Dipl.Chem. (ETH Zurich) ACADEMIC POSITIONS: since 2015: Senior Scientist at EPFL 2009-2015: SNSF-funded Professor at EPFL 2005-2009: Group leader, Fritz-Haber-Institute of the Max-Planck-Society in Berlin (Department of Molecular Physics under Prof. G. Meijer) 2002-2005: Postdoctoral Fellow at UC Berkeley (Group of Prof. D.M.Neumark) 1998-2002: PhD Student at ETHZ (Group of Prof. F.Merkt)

Official source

Ontological neighbourhood

Physics

Thermodynamics: Statistical mechanics

Related concepts (32)

Canonical ensemble

In statistical mechanics, a canonical ensemble is the statistical ensemble that represents the possible states of a mechanical system in thermal equilibrium with a heat bath at a fixed temperature. The system can exchange energy with the heat bath, so that the states of the system will differ in total energy. The principal thermodynamic variable of the canonical ensemble, determining the probability distribution of states, is the absolute temperature (symbol: T).

Entropy (statistical thermodynamics)

The concept entropy was first developed by German physicist Rudolf Clausius in the mid-nineteenth century as a thermodynamic property that predicts that certain spontaneous processes are irreversible or impossible. In statistical mechanics, entropy is formulated as a statistical property using probability theory. The statistical entropy perspective was introduced in 1870 by Austrian physicist Ludwig Boltzmann, who established a new field of physics that provided the descriptive linkage between the macroscopic observation of nature and the microscopic view based on the rigorous treatment of large ensembles of microstates that constitute thermodynamic systems.

Microcanonical ensemble

In statistical mechanics, the microcanonical ensemble is a statistical ensemble that represents the possible states of a mechanical system whose total energy is exactly specified. The system is assumed to be isolated in the sense that it cannot exchange energy or particles with its environment, so that (by conservation of energy) the energy of the system does not change with time. The primary macroscopic variables of the microcanonical ensemble are the total number of particles in the system (symbol: N), the system's volume (symbol: V), as well as the total energy in the system (symbol: E).

Grand canonical ensemble

In statistical mechanics, the grand canonical ensemble (also known as the macrocanonical ensemble) is the statistical ensemble that is used to represent the possible states of a mechanical system of particles that are in thermodynamic equilibrium (thermal and chemical) with a reservoir. The system is said to be open in the sense that the system can exchange energy and particles with a reservoir, so that various possible states of the system can differ in both their total energy and total number of particles.

Microstate (statistical mechanics)

In statistical mechanics, a microstate is a specific configuration of a system that describes the precise positions and momenta of all the individual particles or components that make up the system. Each microstate has a certain probability of occurring during the course of the system's thermal fluctuations. In contrast, the macrostate of a system refers to its macroscopic properties, such as its temperature, pressure, volume and density.

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