Computational studies of pressure effects on complex systems

Dr. Heather Wiebe
Department of Chemistry
Vancouver Island University

January 22, 2024
Time: 1:00 p.m. to 2:00 p.m. 
Room: CSF 1302

Abstract:

High pressure environments are prevalent in our universe, ranging from the relatively modest pressure of the deep ocean to the extreme high pressure of planetary cores. Unlike temperature, which accelerates all elementary reactions regardless of their mechanism, increases in pressure will favour only those reactions that yield a decrease in the volume of the system.  Application of pressure can therefore induce some very interesting and unexpected chemical, physical and electronic transformations. Pressures on the order of 1 kbar will result in the unfolding of most proteins, due to the loss of internal cavities and hydration of previously buried amino acid residues in the unfolded state.[1] Extreme high pressures can result in surprising changes in the electronic properties of materials, such as the recent discovery of solid metallic hydrogen at 4.25 Mbar.[2]

Unfortunately, extreme high pressure conditions are difficult and expensive to generate in a laboratory setting. Molecular dynamics simulations provide an attractive alternative for studying processes at high pressure. Research in the Wiebe group is focused on quantifying the volumetric and thermodynamic changes occur as a result of high pressure in complex systems. In this talk, I will review our recent work on the kinetic isotope effect in liquid metallic hydrogen using path integral molecular dynamics, and our investigation into the physico-chemical mechanism of pressure resistance in proteins from deep-sea organisms using alchemical free energy calculations and Archimedean displacement volumes.

[1] J. Roche et al, Proc. Natl. Acad. Sci. USA, 109, 6945-6950 (2012)
[2] P. Loubeyre et al, Nature, 577, 631-645 (2020)