2. Methodology of Thermodynamics and Statistical Mechanics
Thermodynamics
study of the relationships between macroscopic properties
Volume, pressure, compressibility, …
Statistical Mechanics (Statistical Thermodynamics)
how the various macroscopic properties arise as a
consequence of the microscopic nature of the system
Position and momenta of individual molecules (mechanical
variables)
Statistical Thermodynamics (or Statistical Mechanics) is a
link between microscopic properties and bulk (macroscopic)
properties
3. A collection of particles - system
A collection systemts – ensembles
The systems may have same
macroscopic proterties and
may have different
microscopic properties.
5. represents states of a mechanical system in
thermal equilibrium with a heat bath at a
fixed temperature.
system can exchange energy with the heat
bath, so that the states of the system with
differ in total energy.
6. Canonical Ensemble
Large reservoir (constant T)
All the ensemble members have
the same (n, V, T)
Energy can be exchanged but
particles cannot
Number of Systems : N
N ∞
7. Grand Canonical Ensembles
represents the possible states of a mechanical
system of particles that are in thermo-dynamic
equilibrium (thermal & chemical) with a reservoir.
system is said to be open in sense that the
system can exchange energy and particles with a
reservoir.
So that the system can differ in bath their total
energy and total no. of particles.
8. Large reservoir (constant T )
All the ensemble members have
the same (V, T, mi )
Energy and particles can be exchanged
Number of Systems : N
N ∞
9. Micro canonical ensembles
represents the possible states of a
mechanical system whose total energy is
exactly specified.
System is assumed to be isolated in the sense
the energy of the system does not change
with time.
10. Micro Canonical Ensembles
EVN EVN EVN
impermeable
All the ensemble members have
the same (E, V, N)
there is no transfer of Energy
and mass
isolated
11. Gibbs,Josiah willard(1902). Elementary
principles in Statistical Mechanics.New York:
Charles Scribner’s Sons.
Cercignani,Carlo,(1998). Ludwig Boltzmann:
The Man Who Trusted Atoms. Oxford
University Press. IsBN 9780198501541.
Huang, Kerson(1967). Statistical Mechanics.
John Wiley & Sons.
Srivastava, R.K; Ashok, J.(2005). Statistical
Mechanics. New Delhi: PHI Learning Pvt.Ltd.
ISBN 9788120327825.
