Statistical Thermodynamics & Molecular Simulations (STMS) Seminar Series
These seminar series, which are supported by AIChE’s Computational Molecular Science & Engineering Forum (COMSEF), are aimed at providing a virtual platform for sharing scientific research in the area of statistical mechanics, molecular simulations, and computational materials science. In recent months, the coronavirus pandemic has stopped all large in-person scientific gatherings, including conferences and department seminars, and it is not clear that the situation will improve any time soon. STMS is aimed at filling this gap, and provide a venue for dissemination of research findings and exchange of ideas in the age of COVID. This model is being currently used by several other scientific communities, and can potentially continue even beyond the pandemic if successful.
Each seminar will be a 60-minute event and will comprise of a long-form (30-minute) talk by a principal investigator or a senior research scientists from academia or industry and a short-form (15-minute) presentation by a graduate student or a postdoc. The remainder of the event will be dedicated to Q&A (10 minutes for the PI, 5 minutes for the student/postdoc). Long-form speakers will be chosen by the STMS Organizing Committee, while we encourage suggestions from the community at large. Student and postdoctoral speakers, however, need to be nominated by their advisors. Seminars will take place on Fridays, from 11 AM-12 PM. During 2020, we expect to hold one seminar per month. The dates and the frequency of seminars for 2021 will be decided soon.
This event's talks:
Modeling the kinetics of antifreeze protein adsorption: Buffon’s needle at the molecular scale
Prof. Baron Peters (University of Illinois, Urbana-Champaign)
Abstract: Nature has developed many antifreeze proteins (AFPs) that arrest ice growth at temperatures far below 0oC. Some of the most potent AFPs are long stiff helical coils. The efficacy of an AFP is thought to depend on its adsorption free energy, its adsorption kinetics, and its susceptibility to engulfment in ice. In experiments with systematically modified helical AFPs, extra coils were added to investigate the effect of helical AFP length. Additional coils should reduce engulfment susceptibility and increase binding strength, effects that should both increase ice inhibition efficacy. However, the experiments find an optimum length beyond which additional coils reduce the AFP efficacy, suggesting that long helical AFPs may lose efficacy because of slow adsorption. To adsorb on the ice surface, a helical AFP must approach the surface and rotate into a specific orientation. The range of AFP orientations become increasingly restricted as the AFP approaches the surface, leading to an entropically denuded layer that impedes adsorption. By treating the helical AFP as a Brownian needle, we develop a non-equilibrium rate theory for AFP attachment by diffusion through this denuded layer. We compare the analytic theory to results from Brownian dynamics simulations and discuss current atomistic simulation efforts.
Speaker Bio: Baron Peters (from Moberly, Missouri, 1976 - ) is W. H. and J. G. Lycan Professor of Chemical and Biomolecular Engineering at the University of Illinois at Urbana-Champaign. He completed B.S. degrees in Chemical Engineering and Mathematics at the University of Missouri - Columbia. He studied catalysis and reaction rate theory for a PhD with Alex Bell and Arup Chakraborty at the University of California - Berkeley in 2004. He did post-doctoral research with Bernhardt Trout at the Massachusetts Institute of Technology and with Berend Smit at the Centre Europeen de Calcul Atomique et Moleculaire (CECAM). He then held ranks of Assistant, Associate, and Full Professor at the University of California – Santa Barbara (2007 – 2018) before moving to the University of Illinois in 2019. Baron has contributed leading computational methods and theories in the areas of reaction and nucleation kinetics. Baron also authored “‡” in 2017, the first comprehensive textbook on reaction rate theories and rare events methods. Baron currently works on several problems in the areas of crystal nucleation and growth and on catalysts for polymerization and polymer recycling.
Liquid-liquid critical point in realistic models of water
Dr. H Gül Zerze (Princeton University)
ABstract: The hypothesis that water may possess a second critical point located at deeply supercooled conditions was formulated in an effort to provide a thermodynamically consistent interpretation for numerous experimentally-observed anomalies of water. While the preponderance of evidence is consistent with the existence of a second critical point, no unambiguous experimental proof has been found to date. Computer simulations can bypass the main challenge to experiments, rapid crystallization, but require computational efforts that prevented the rigorous verification of the presence of a second critical point in accurate water models up to now. Here, we use histogram reweighting and large-system scattering calculations to investigate computationally two molecular models of water, TIP4P/2005 and TIP4P/Ice, widely regarded to be among the best classical force fields for this substance. We show that both models possess a metastable liquid-liquid critical point at deeply supercooled conditions and that this critical point is consistent with the 3-d Ising universality class. Next generation challenges in this field include i) bringing higher accuracy (i.e. quantum mechanical accuracy) models to better performance so that above mentioned analyses (finite-size scaling via histogram reweighting and large-system scattering) would be possible to perform ii) developing advanced sampling techniques to accelerate sampling of slow-relaxation events, such as long-range correlations near criticality.
Speaker Bio: Gül received her bachelor’s degree (2010) and master’s (2013) degree in Chemical Engineering from Middle East Technical University (Turkey) as a fellow of the Scientific and Technological Research Council of Turkey. She joined Chemical and Biomolecular Engineering at Lehigh University in 2013 and received her Ph.D. in 2017. She has continued her work as a postdoctoral researcher at Princeton University where she has been named as a Writing in Science and Engineering Postdoctoral Fellow (2020). She has also been the recipient of awards including TSCR Peter Salamon Award, Biophysical Society’s Research Achievement Award, Chevron Corporation’s Recognizing Excellence Award, and AICHE COMSEF Graduate Student Award.