The number F is a constant for the ensemble. It can take on a range of values depending on the temperature. An ensemble with these three parameters is sometimes called the NVT ensemble; the canonical ensemble assigns a probability P to each distinct microstate given by the following exponential: P = e F − E k T, where E is the total energy of the microstate, k is Boltzmann's constant. Microcanonical ensemble means an isolated system with defined energy. English Etymology . These microcanonical ensembles are physical systems in which the volume, energy and total number of particles are held constant. A microcanonical ensemble consists of systems all of which have the same energy and is often found useful in describing isolated systems in which the total energy is a constant. Wikipedia . 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. In the microcanonical ensemble, the total energy is fixed, but in the canonical ensemble the energy is no longer constant. Microcanonical NVE ensemble (no collisions with the thermostat) Canonical ensembe at T= 10K, to be close to the standard relaxation (0K) To keep the computing time reasonable, the number of steps in the MD is limited to 100 (100 fs) which implies that the MD is NOT CONVERGED. microcanonical (not comparable) Uniqueness: The canonical ensemble is uniquely determined for a given physical system at a given temperature, and does not depend on arbitrary choices such as choice of coordinate system (classical mechanics), or basis (quantum mechanics), or of the zero of energy. In statistical mechanics, a micro-canonical ensemble is the statistical ensemble that is used to represent the possible states of a mechanical system that has an exactly specified total energy. Canonical ensemble-- an ensemble of systems, each of which can share its energy with a large heat reservoir or heat bath (in effect, fixing the temperature). micro-+ canonical. Definition from Wiktionary, the free dictionary. English Wikipedia has an article on: microcanonical ensemble. The canonical and the microcanonical ensemble We could now ask how the microcanonical and the canonical ensembles are related. microcanonical. Adjective . Since in the canonical ensemble we have removed the constraint of having constant energy, the energy of a system will in general fluctuate around its mean value.
Microcanonical ensemble-- an ensemble of systems, each of which is required to have the same total energy (ie thermally isolated). The system can exchange energy with the heat bath, so that the states of the system will differ in total energy. The system may be found only in microscopic state with the adequate energy, with equal probability. Jump to navigation Jump to search. Statistical thermodynamics provides this connection by averaging the microscopic values across a large set of microcanonical ensembles at an instant in time to arrive at macroscopic values. Canonical ensemble means a system attached to the "temperature reservoir", which may supply/take infinite amount of energy. A microcanonical ensemble of classical systems provides a natural setting to consider the ergodic hypothesis, that is, the long time average coincides with the ensemble average. More precisely put, an observable is a real valued function f on the phase space Γ that is integrable with respect to the microcanonical ensemble measure μ.