Monday, Feb. 14, 3:30-4:30pm, WEL 2.122
Assistant Professor
Southern Methodist University
PhD, UC Berkeley, 2013
Abstract: The principles governing charge and energy transport in novel molecular semiconductors are often obscured by the complex interplay of structural heterogeneities, interfaces, and disorder on the nanometer-to-micron length scale (i.e., the mesoscale). To engineer novel molecular materials that enable next-generation technologies, we need a predictive understanding of how excited-state carriers – such as excitons, electrons, and holes – move through heterogeneous mesoscale systems. However, most computational methods remain intractable for mesoscale molecular materials where the number of molecules is massive, and the material parameters tend to fall into the broad “intermediate regime” where perturbative techniques breakdown. In this talk, I will discuss recent developments in my group that have enabled the first formally-exact mesoscale simulation of exciton dynamics and spectroscopy in molecular materials. These developments offer a glimpse of a new class of quantum dynamics methods that can illuminate photophysical mechanisms of realistic molecular materials.
Publications (Google Scholar Citations)
h-index: 12 Total Citations: 529 (Google Scholar Citations, Jan 2022)
Monday, Feb. 7, 3:30-4:30pm, WEL 2.122 / ZOOM
Postdoctoral Scholar
UC Irvine
PhD, Univ. of South Carolina, 2016 (Sophya Garashchuk)
Abstract: The advent of quantum light such as entangled photons has opened up new possibilities to nonlinear molecular spectroscopy. The quantum spectroscopy can extract matter information not available by classical light. We will discuss the advantages of using entangled photons for two-photon absorption over the classical counterpart in terms of light intensity requirements, spectral and temporal resolution, and control of photochemical reactions. Similarly, vacuum field in an optical microcavity provides a new platform for coherent control techniques. We will demonstrate how the strong light-matter coupling between the cavity field and embedded molecules can be exploited to manipulate the ultrafast photochemical processes. Examples include the singlet fission in pentacene, internal conversion in pyrazine molecules, and ring currents in metalloporphyrin.
Publications (Google Scholar Citations)
h-index: 13 Total Citations:357 (Google Scholar Citations, Jan 2022)
Wednesday, Feb. 2, 3:30-4:30pm, WEL 2.122
Postdoctoral Researcher
University of Chicago
PhD, Lomonosov University (Moscow)
Abstract: Electrostatically driven phase separation in solutions of the oppositely charged polyelectrolytes (referred to as complex coacervation) and solutions of polyampholytes (called self-coacervation) is currently viewed as the basic physical model describing intracellular organization and the formation of membrane-less organelles. Coulombic attractions between the opposite charges within the polymer-rich phase are due to their positional charge correlations, and statistical physics of ionic polymers can be fruitfully applied to gain valuable insight into these phenomena. First, I will focus on how the equilibrium and dynamics properties of the polymer-rich complex coacervate phase are affected by (i) salt concentration, (ii) solvent quality, (iii) stiffness of polyelectrolytes, (iv) their incompatibility, and (iv) sequence of ionic and neutral monomers in them. I will then discuss the conformational behavior of single-chain sequence-defined polyampholytes modeling intrinsically disordered proteins (IDPs). For polyampholytes/IDPs with a non-zero net charge, the interplay between sequence-dependent correlation-induced attractions and bare Coulombic repulsions results in different conformations including spherical globules, “necklaces” of various structures containing several smaller globules, and strongly stretched chains.
Publications (Google Scholar Citations)
h-index: 15 Total Citations: 637 (Google Scholar Citations, Jan 2022)
Monday, January 31, 3:30-4:30pm
Postdoctoral Researcher
Yale University
PhD, Harvard, 2020 (Eric Heller)
Publications (Google Scholar Citations)
ORCID: https://orcid.org/0000-0001-7973-2842
h-index: 2 Total Articles: 7 Total Citations: 15 (Web of Science, Jan. 2022)
h-index: 3 Total Citations: 20 (Google Scholar Citations, Dec. 2021)
Thursday, January 27, 3:30-4:30pm, WEL 2.122
Postdoctoral Researcher
Yale University
PhD, Univ. of Buenos Aires, 2015
Abstract: Understanding how interfaces modulate the orientation, energetics and reactivity of molecular systems is of crucial importance in a variety of areas, including heterogeneous catalysis, energy conversion and atmospheric chemistry. In recent years, the development of nonlinear surface-selective vibrational spectroscopy, such as Sum Frequency Generation (SFG) spectroscopy, has opened the possibility to study interfacial molecules with unprecedented levels of detail. In this talk, I will describe our recent work on characterizing molecular catalysts at electrochemical interfaces with SFG spectroscopy. Experimental measurements show pronounced potential-dependent frequency shifts of the vibrational spectra. Our computational results allow rationalizing these findings in terms of large interfacial electric fields, providing a direct connection between the applied voltage (an experimentally controllable parameter) and the interfacial electric field, a macroscopic property of the electrode/electrolyte interface.
Publications (Google Scholar Citations)
h-index: 8 Total Articles: 25 Total Citations: 268 (Web of Science, Jan. 2022)
h-index: 9 Total Citations: 343 (Google Scholar Citations, Dec. 2021)
Thursday, January 13, 3:30-4:30pm, WEL 2.122
Postdoctoral Scholar
Stanford University
PhD, Wisconsin (Josh Coon)
Abstract: Technology to capture dynamic and complex states of the proteome continues to progress at an exciting pace. Despite this, characterization of extracellular (i.e., cell surface and secreted) proteins – a subset of the proteome critical for understanding intercellular interactions that govern numerous biological processes – remains challenging. Here I will discuss efforts to improve chemical instrumentation, bioinformatic platforms, and molecular manipulations to study the layers of complexity within the extracellular proteome. These include new approaches to characterize glycoproteins, which are dominant features of the extracellular space, and methods to dissect dynamic and cell-type specific contributions to the secretome using in vivo mammalian systems. Together these studies show how the confluence of bioanalytical chemistry and chemical biology can advance our abilities to probe the extracellular proteome in complex systems and open windows to new biological questions.
Publications (Google Scholar Citations)
ORCID: https://orcid.org/0000-0002-1536-2966
h-index: 23 Total Articles: 39 Total Citations: 1237 (Web of Science, Jan. 2022)
h-index: 25 Total Citations: 1645 (Google Scholar Citations, Dec. 2021)
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