BMECHE Research Seminar - David Kofke (Univ at Buffalo)

David Kofke, Ph.D.
SUNY Distinguished Professor of Chemical and Biological Engineering
University at Buffalo

The “Easy” Thermodynamic Phases Can Provide Interest, Challenge, and Opportunity

Among the three common phases of matter, the liquid is the most difficult to understand and predict, and accordingly has attracted much of the attention of the molecular modeling community. Nevertheless, crystals and gases are important too, and pose interesting problems of their own. The relative ease of their description opens up opportunities for first-principles calculations, with accuracy sometimes exceeding experiment. Such capabilities can support new high-throughput approaches to design of many engineered systems.

The virial equation of state provides the standard treatment for the gas phase, yet because of the difficulty in computing the virial coefficients its general utility is largely unexplored. Can it, for example, provide a general location for the critical point? What is its convergence behavior when applied to realistic systems? Why are many popular molecular models so poor at reproducing experimental virial coefficients, and should these data be used more in guiding model formulation? We show the considerable advances that have been made on these questions over the past decade.

The solid phase is described reasonably well with harmonic analysis, but when using conventional simulation methods this good starting point provides no assistance in making simulations faster or more efficient. A new “mapped averaging” framework has remedied this problem by removing harmonic contributions to properties. Then, direct measurement of the remaining anharmonic contributions by molecular simulation can be accomplished without noise from the harmonic behavior, producing results of exquisite precision. We demonstrate with some recent applications to calculation of elastic constants of crystalline materials.

In-person 73-1180 and Zoom: https://rit.zoom.us/j/96134371398


Contact
Tom Gaborski
Event Snapshot
When and Where
February 24, 2022
12:30 pm - 1:30 pm
Room/Location: 1180
Who

Open to the Public

Interpreter Requested?

No