# Free Energy Calculations and the Potential of Mean Force

Tuesday, July 24, 2007 - 9:30am - 10:30am

EE/CS 3-180

Mark Tuckerman (New York University)

The free energy plays a central role in statistical mechanics and is a key

quantity of experimental interest. The free energy is equal to the reversible

work needed to effect a thermodynamic process and is the

generator of other thermodynamic properties in a given statistical ensemble.

Free energies are directly related to equilibrium constants (for example,

the efficacy of a drug is measured by an equilibrium constant known as the

inhibition constant, which is related to the binding free energy between an inhibitor

and its target enzyme) and chemical potentials, and can be used to estimate

rate constants. Obtaining accurate free energies is challenging because of

the inability of straightforward simulation techniques to sample phase space

sufficiently. In this lecture, we will introduce the concept of free energy and discuss

a number of state-of-the-art techniques for enhancing phase-space sampling,

particularly when the sampling is hindered by so-called rare events.

quantity of experimental interest. The free energy is equal to the reversible

work needed to effect a thermodynamic process and is the

generator of other thermodynamic properties in a given statistical ensemble.

Free energies are directly related to equilibrium constants (for example,

the efficacy of a drug is measured by an equilibrium constant known as the

inhibition constant, which is related to the binding free energy between an inhibitor

and its target enzyme) and chemical potentials, and can be used to estimate

rate constants. Obtaining accurate free energies is challenging because of

the inability of straightforward simulation techniques to sample phase space

sufficiently. In this lecture, we will introduce the concept of free energy and discuss

a number of state-of-the-art techniques for enhancing phase-space sampling,

particularly when the sampling is hindered by so-called rare events.