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Statistical mechanics/Thermodynamics



The previous post hints about the contribution of Statistical mechanics in Molecular Dynamics.
Looking at the definition of the words Statistics and Mechanics:

Statistics is the science that deals with the collection, classification, analysis, and interpretation of numerical facts or data, and that, by use of mathematical theories of probability, imposes order and regularity on aggregates of more or less disparate elements.

Mechanics is the branch of physics that deals with the action of forces on bodies and with motion, comprised of kinetics and statics.

If in addition if one learn the definition of thermodynamics, a science concerned with relation of heat, work and energy and their interconversions, one can try to understand statistical mechanics/ thermodynamics and its connection with Molecular dynamics.

Thus in Statistical mechanics/ thermodynamics one applies the mathematical theories of probability to study thermodynamic behavior associating heat, work and energy of systems composed of large number of particles which are mostly in motion owing to action of forces on these particles.

Thus Statistical mechanics/Thermodynamics acts as a bridge in the form of probability theory connecting microscopic properties of individual atoms and molecules to the thermodynamic properties of the system formed from these microscopic particles.

Statistical thermodynamics calculates the distribution of a given amount of energy E over N identical systems. It helps to interpret the measurable macroscopic properties of system as a function of properties of the constituent particles and the interactions between them. This is done by connecting thermodynamic functions to quantum-mechanical equations. Partition function and the Boltzmann distributution function are the two important pillars of the bridge of statistical thermodynamics connecting bulk thermodynamic properties and the individual atom/molecular properties.


Another factor important from the point of view of Statistical thermodynamics is the physical description of the system. An ensemble provides this physical description which crudely is a collection of all possible configurations of the system with different microscopic states but an identical macroscopic or thermodynamic state.

 For a simplified graphical tour of Statistical thermodynamics, no better place than this link:
http://www.physics.sfsu.edu/~gmarcy/smgraphical.html

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