## Statistical Mechanics of Liquids

*Dr. Abhinav Sharma, IPF, Dresden *

One way to define a liquid is a collection of particles interacting with each other with no long range order. The interaction is much stronger than in the gas phase making liquids generally incompressible. Yet the thermal fluctuations do not allow a liquid to have any long range structural order making the liquid phase distinct from the solid phase. So what structure does a liquid have? How does one calculate the pressure in liquids? What is ionic liquid ? What is osmotic pressure and how to calculate it? In this course, we will take equilibrium statistical mechanical approach to address these questions and understand physical properties of liquids.

The following topics will be covered:

1. Imperfect gases

2. Radial distribution function of liquids

3. Perturbation theories of liquids

4. Ionic liquids etc.

The course will be built on fundamental concepts such as classical partition function and distribution functions. The course is aimed at Master students from Physics, Biophysics and Chemistry.

**Background Needed:** Basic course in statistical mechanics, open mind **Keywords:** Partition function, Virial equation, Density expansions, perturbation theories, Debye-Hückel Theory, Ionic solutions, Osmotic pressure. **Course Schedule:** Every Thursday starting 11th April 2019, 4.DS, Room REC/D16/U**Assignments and Exam:** There will be 6 assignments in total and no exam.

Pair correlation function of a typical liquid. The molecules of liquids interact with each other via Lennard-Jones potential. σ is diameter of the particle and *r* is the distance between a pair of particles. The peaks show that there is significant ordering of particles giving local structure to liquids.