The eSSENCE of . . . Computational & Theoretical Chemistry and Physics

Wednesday 25 November, Å 4001 at 10.15

Dr. Kjartan Thor Wikfeldt, Stockholm University

“Simulating challenging systems using adaptive kinetic Monte Carlo
and ab initio path-integral molecular dynamics”

Dramatic advances in high-performance computing coupled with the
development of new and improved simulation algorithms are enabling
researchers to obtain molecular-level information on physical, chemical
and biological systems in ever greater detail. However, many systems
still pose a challenge to conventional simulation techniques such as
molecular dynamics (MD). Two types of system that cannot be described
using standard MD are (1) rare-event systems, where interesting processes
take place on timescales much longer than a microsecond, and
(2) systems where quantum effects such as zero-point motion and
tunneling play a decisive role.

In this talk, two projects will be described where state-of-the-art simulation
methods have been applied to overcome these drawbacks of standard MD.
In the first, adaptive kinetic Monte Carlo simulations have been used to
elucidate the structure and molecular reordering processes taking place on
ice surfaces. In the second, ab initio path-integral MD simulations have
been used to investigate the order-disorder phase transition in a
prototypical hydrogen-bonded ferroelectric crystal, in which quantum
tunneling of hydrogen atoms is key to the behavior of the system.


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