LANS Informal Seminar: Michael Servis

Seminar Title: Advanced Modeling and Simulation of Solvent Extraction Systems – How Topological Data Analysis is Changing the Simulation Landscape
Speaker: Michael Servis, Postdoctoral Researcher, Washington State University

Date/Time: 2018-12-12 11:00
Location: Bldg. 240, Rm. 4301

Description:
Molecular dynamics simulation is an emerging tool to describe complex solution phase
association of molecular species, including solutions with applications to liquid/liquid
separations. While simulations provide exact molecular positions, meaningfully quantifying the
association and structure of those molecules requires additional modeling or analysis. This talk
will cover several examples of generating insight into solution phase behavior using graph
theoretic descriptions of molecular-scale correlations. In the first topic, intermolecular
connectivity of liquid water is represented using graph theory. Molecular motions are identified
through so-called transition matrices, where patterns in the changing connectivity between
neighboring water molecules are identified to understand the dynamic pathways between
configurations. In the second topic, PageRank is used to uniquely map the local connectivity
pattern of an ion in solution to a single collective variable. That collective variable then can be
used to drive the solvation environment of the ion in simulation from one structure to another
through PageRank space. Lastly, simulations show that water protrusions form at the
surfactant-laden liquid/liquid interface, leading to transfer of water between phases.
Understanding the role of the surfactant in promoting protrusions, and therefore water
transport, requires algorithmic identification of such interfacial features. We demonstrate that
those protrusions can be identified by their spatial connectivity using network analysis.