Seminars & Events

Throughout the academic year, the department hosts several seminars whose presenters range from department graduate students to internationally renowned professors and scientists. The calendar below includes all of our department seminars and events. It is updated frequently with titles and abstracts — you can subscribe using Google Calendar by clicking the "+GoogleCalendar" button in the lower right. 

Seminars

Friday Colloquium Series

Faculty members and graduate students invite professors from other institutions throughout the country and the world to speak at Brown on a Friday afternoon. Friday colloquiua topics span the various fields of chemistry represented by the department. Sometimes, a colloquium seminar is hosted jointly with another department or institute, such as IMNI, the Institute for Molecular and Nanoscale Innovation. Friday afternoons, 3:00pm - 4:00pm, MacMillan Hall 115. Refreshments served at 2:45pm.

Organic Chemistry Seminars

Organic chemistry graduate students are required to give at least two seminars. The first is a literature seminar on a topic of recent interest, and the second is the candidate's thesis research. Invited guests frequently present their research at Organic Seminars as well. Tuesday afternoons, 12:00pm - 1:00pm.

Inorganic Chemistry Seminars

Inorganic chemistry graduate students are expected to present one seminar per year on their own research or on another topic of current interest in inorganic chemistry. Research associates, faculty and invited guests often present inorganic seminars as well. Thursday afternoons, 12:00pm - 1:00pm.

Physical Chemistry Tea Sessions

Physical chemistry graduate students are expected to present one seminar per year. Topics covered include the graduate students' topics of interest with regard to current research, as well as their own research. Thursday afternoons, 3:00pm - 4:00pm.

 

Upcoming Events

  • Title: Dynamics and Emergent Complexity in Functional Nanocrystals and Nanocrystal Superstructures

    Abstract: Functional materials built from nanocrystals and nanocrystal superstructures are enabling new applications in energy conversion and storage, optoelectronics, nanomedicine, among others. Essential to the realization of materials-by-design is to elucidate synthetic pathways and understand the kinetics of structural transitions. The process of nanocrystal assembly, analogous to a chemical reaction, usually traverses a complex free-energy landscape before reaching the final state. Therefore, we must begin to think of assembly as a reaction pathway connecting multiple nonequilibrium intermediates. Fully understanding these pathways requires real-space, real-time characterization with meaningful spatiotemporal resolution, which is not by possible with existing ex-situ characterization or scattering-based techniques. In the first part of this talk, I will discuss our recent advances on direct imaging of nanocrystal assembly using in-situ liquid cell transmission electron microscopy. The interaction potential between nanocrystals can be readily tuned by changing the solvent, which enabled observation and quantitative analysis of nonclassical crystallization pathways for nanocrystal superstructures. In the second part of this talk, I will introduce our work on creating shape-controlled dilute metal alloy nanocrystals by establishing distinct synthetic pathways during seeded-mediated growth. These well-defined nanocrystals are promising electrocatalysts for high-rate, selective conversion of chemical feedstocks into value-added products.

    Bio: Dr. Xingchen Ye is currently an Assistant Professor in the Department of Chemistry at Indiana University Bloomington (IUB). Prior to joining IUB in 2017, he was a postdoctoral fellow at UC Berkeley working with Prof. Paul Alivisatos. He earned his PhD in Chemistry from University of Pennsylvania in 2012 under the tutelage of Prof. Christopher Murray and a B.S. in Chemistry from University of Science and Technology of China. Dr. Ye has received multiple research awards from the National Science Foundation (NSF) including the CAREER award and is a founding member of the recently established NSF Center for Single-Entity Nanochemistry and Nanocrystal Design (C-SENND). The Ye group focuses on precision synthesis of colloidal nanomaterials and their superstructures for energy applications as well as utilizing in-situ electron microscopy techniques to elucidate nanoscale dynamics and materials transformation.

    Chemistry Colloquium with Xingchen Ye • Indiana University, Bloomington •Dynamics and Emergent Complexity in Functional Nanocrystals and Nanocrystal Superstructures
  • Oct
    12
    3:00pm - 5:00pm

    Chemistry Graduate Poster Symposium

    MacMillan Hall
  • Oct
    13
    3:00pm - 4:00pm

    Chemistry Department Undergraduate Open House

    MacMillan Hall

    Our faculty, grad students and ChemDUG will answer your questions about our labs, research opportunities and becoming a Chemistry Concentrator! Sign up here!

    Light refreshments will be served.

    Chemistry Department Undergraduate Open House
  • Oct
    18
    10:00am - 11:30am

    Chemistry Careers with Pfizer!

    Geo-Chem Building

    Join the Chemistry Department in welcoming Pfizer to Brown! Learn about what it takes to be a Medicinal and Process chemist and what goes into discovering and developing breakthrough medicines!

    There will be a Q&A session after the presentation. 

    Chemistry Careers with Pfizer!
  • Networks of (bio)molecular switches and motors built with nucleic acids

    Complex cellular behaviors such as motion and division are directed by far-from-equilibrium chemical networks that sense a cell’s environment and in turn regulate the assembly and reconfiguration of a cell’s architecture at the molecular scale. Inspired by these examples, we are developing molecular sensors, information processing networks, and actuators that can be coupled to enable the autonomous action of microscale soft robots in response to biomolecular signals. We have recently developed integrated synthetic in vitro genetic regulatory networks consisting of oligonucleotide templates, T7 RNA polymerase, and RNases. These networks can consist of tens of different interconnected network elements, making it possible to construct synthetic regulatory networks of complexities comparable to those of simple viruses. We are asking how one can program the evolution of synthetic materials by controlling how much and when multiple network outputs (RNA strands) are produced. These outputs can modulate, for example, the polymerization and depolymerization of a hydrogel polymer scaffold to drive the motion of a soft robot. To direct the motion of these devices, we are developing molecular sensors that can sense signals of physiological interest, such as forces or proteins and respond by controlling actuation processes.

    Chemistry Colloquium with Rebecca Schulman • Johns Hopkins University • Networks of (bio)molecular switches and motors built with nucleic acids
  • Solvation in Atomic and Electron Crystal s

    Solvation is central to chemistry, e.g., in controlling reaction barriers, in stabilizing or selecting key reaction products, or in preventing unwanted binding of cations with anions. In this lecture, I will discuss our recent attempts of developing concepts akin to solvation, but in atomic or electron crystals. In the first part, we start with the solution-grown crystalline semiconductors, lead halide perovskites, that have shown remarkable optoelectronic performance despite being statically and dynamically disordered. The remarkable defect tolerance may be traced in part to the efficient screening of an electron or hole by extended ordering of local dipoles from symmetry-breaking unit cells; the result of such solvation-like screening is a ferroelectric polaron characterized by “Belgian waffle” like wavefunction, a proposal supported theoretically by ab initio molecular dynamics calculations and experimentally by charge stabilization on the surface of the paraelectric MoTe2 and in the bulk of a Bi2O2Se. The ferroelectric polaron model is found to be equivalent to the well-known chemistry concept of ns2 electron pair expression or the second order Jahn-Teller effect. In the second part, we address the ordering of electrons in 2D moiré materials. Such ordering occurs when electron kinetic energy is much lower than their mutual Coulomb repulsions. Here, we explore the stability origins of ordered electron states in WSe2/WS2 moiré superlattices. We find that ultrafast electronic excitation leads to melting of the ordered electron states on time scales five times longer than predictions from the charge hopping integrals and the melting rates are thermally activated, with activation energies of 13-18 meV, suggesting significant electron-phonon coupling. DFT calculation confirms polaron formation and yields a polaron binding energy of 16 meV. Our finding for the ordered electron state in the TMD moiré system suggests that electron-phonon interactions may be responsible for the observed thermal stability and may therefore be key to searching for high Tc correlated 2D electrons.

    Chemistry Colloquium with Xiaoyang Zhu • Columbia University • Solvation in Atomic and Electron Crystals
  • Nov
    3
  • Visualizing materials functionality at the atomic scale and in real time.

    Abstract: A central problem in condensed matter physics and chemistry is to understand the fundamental coupling mechanisms between electrons and ions and the emergent phenomena that arise from these microscopic interactions. This understanding in turn can enable new means for for controlling and inducing novel phases of matter with unique functionalities. In this talk I will describe two recent efforts which illustrate these approaches: (1) I will show experimental results which demonstrate a new type of non-resonant optomechanical control in which the electric field of light stabilizes new structural phases of matter with interesting optoelectronic properties. This work defines novel types of phase-change materials with ultralow switching energies and ultrafast switching speeds and new low energy routes towards inducing non-equilibrium quantum phases of matter. (2) I will introduce femtosecond-resolution electron scattering experiments probing the dynamic microscopic interactions between excitons and the lattice in a class of lead-halide hybrid perovskite quantum dots. Understanding the origins of electron-phonon coupling in these materials is key to interpreting and leveraging their unique optoelectronic properties. I will show how our measurements enable direct visualization and quantification of exciton-lattice coupling. We further demonstrate that concerted, symmetry enhancing reorganizations induced by each exciton in a multi-excitonic state constructively interfere, giving rise to a coupling strength which scales quadratically with exciton number. This super-linear scaling induces a new type of phonon-mediated attractive interaction between excitons in the perovskites and opens up new opportunities for controlling dynamic disorder in disordered and polymorphic structures.

    Chemistry Colloquium with Aaron Linderberg • Stanford University • Visualizing materials functionality at the atomic scale and in real time.
  • Mark Johnson is the Arthur T. Kemp Professor in the Department of Chemistry at Yale University. Johnson is known for the development and exploitation of experimental methods that capture and structurally characterize transient chemical species such as reaction intermediates. Most important among these is his exploitation of cryogenic ion chemistry in conjunction with multiple resonance laser spectroscopy. Johnson was born and in Oakland, California in 1954 and raised in the San Francisco Bay Area. He graduated from the University of California at Berkeley with a degree in chemistry and a first exposure to fundamental research under the mentorship of C. Bradley Moore. He then earned his Ph.D. from Stanford University in 1983 with Dick Zare, which involved an extensive collaboration with Joëlle Rostas at the Université de Paris-Süd. He was a postdoctoral fellow with Carl Lineberger at JILA/University of Colorado, Boulder from 1983-1985 and joined the Yale faculty in 1985. He rose rapidly through the ranks and has held the Arthur T. Kemp Professorship since 2006. He has served as Chair of APS Division of Laser Science and the ACS Division of Physical Chemistry, and was co-editor of the Annual Review of Physical Chemistry from 2012 to 2022. He has been elected to Chair three Gordon Research Conferences (Molecular and Ionic Clusters (1996), Photoions (2001), and Gaseous Ions: Structures and Energetics (2015)).

    2024 Appleton Lecture with Mark Johnson • Yale University