Prof. Abhijit Chatterjee

Department of Chemical Engineering, Indian Institute of Technology Bombay

E-mail: abhijit[at]che.iitb.ac.in

 

 

 

 

Brief Bio-sketch:

Dr. Abhijit Chatterjee is an Associate Professor in Chemical Engineering at IIT Bombay. He has been involved in the development of new computational strategies for studying rare events in materials simulations, materials informatics and multiscale problems. Dr. Chatterjee received his bachelor and masters degrees from IIT Delhi, and Ph.D. degree from University of Delaware. Dr. Chatterjee has been at IIT Bombay since 2013 after spending two years in Los Alamos National Laboratory and four years in IIT Kanpur as Assistant Professor. He has received a number of prestigious awards including awards from NASI, INSA, INAE and IE(I).

 

ACCELERATING RARE EVENTS IN MATERIALS SIMULATIONS

Molecular scale events that happen infrequently at molecular dynamics (MD) timescales, i.e., at microseconds or longer, are termed as rare events. The traditional MD approach becomes difficult to apply in situations where rare events are important. New computationally efficient approaches are needed to effectively sample rare events. I will describe two rare event acceleration techniques developed in my research group that can be used to efficiently study long timescale dynamics of materials. Speed-up resulting these methods can be as large as two-six orders of magnitude over traditional MD.A situation commonly encountered in several complex materials, e.g., metals, alloys, semiconductors, ionic solids, is that the system remains trapped for long periods of time in a collection of potential basins in the energy landscape. Escape from these basins involves a large thermal activation barrier. The temperature programmed molecular dynamics (TPMD) method [1] employs a temperature program with MD that allows rare transitions of interest to happen more frequently. A variation of steered molecular dynamics (SMD) simulations [2] is introduced to handle rare events in biomolecular systems. A stretching force applied on a biomolecule causes it to access large end-to-end distances. Under these conditions the biomolecule undergoes rapid conformational changes that are rare at the zero-force conditions. A theory describing kinetics of a biomolecule at various stretching forces is presented. Using the theory rates can be calculated at zero-force conditions from rates at non-zero force conditions.

 

References:

[1] A Chatterjee, Accelerating Rare Events and Building Kinetic Monte Carlo Models Using Temperature Programmed Molecular Dynamics, Journal of Materials Research 33 (7), 835-846

[2] S Bhattacharya, A Chatterjee, Uncertainty Quantification For Markov State Models Of Biomolecules Constructed Using Rare Event Acceleration Techniques, J. Chem. Phys. 150, 044106 (2019).