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

Time: Wednesday, April 11, 2018 - 10:30am - 11:30am
Type: Seminar Series
Presenter: David A. Kofke; Dept. of Chemical and Biological Engineering, SUNY University of Buffalo
Room/Office: Becton 035
Becton Seminar Room
15 Prospect Street
New Haven, CT 06511
United States

Department of Chemical & Environmental Engineering Seminar

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

Distinguished Professor David A. Kofke
SUNY University of Buffalo
Dept of Chemical and Biological Engineering

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? Mixtures are treated exactly in the virial equation, so what can we learn about mixture behavior from it? 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. This advance is demonstrated via first- principles calculation of the properties of metals, and iron in particular at the extreme conditions found at the Earth’s inner core.

Wednesday, April 11, 2018 at 10:30AM
Becton Seminar Room
15 Prospect Street, MC 035

Refreshments at 10:00AM