Events in physical chemistry.

Connecting the dots of immune machinery using a single-molecule lens

Abstract: The human immune system comprises a network of specialized cells and biomolecules that work together to defend the body against attacks by foreign invaders, known as antigens. This intricate network of cells and biomolecules also creates a complex puzzle. While the immune system has the capacity for an almost unlimited range of antigens, how does it achieve exquisite specificity? What enables immune cells to communicate over long distances and orchestrate a bodywide immune response?

How do many-body scattering effects contribute to the excitonic dynamics in semiconductors?

Abstract: Modern multi-dimensional spectroscopy offers a unique look "under the hood" allowing us to probe the dynamics of excitons in semiconducting systems. In this talk, I shall review our recent quantum stochastic model for spectroscopic lineshapes in a co-evolving and non-stationary background population of excitations. Starting from a field theory description for interacting bosonic excitons, we derive a reduced model whereby optical excitons are coupled to an incoherent background via scattering as mediated by their screened Coulomb coupling.

Modeling of electrostatic and chemical properties of nanoscopic and microscopic aerosol droplets

Abstract: Atmospheric and man-made droplet aerosols show many commonalities in their physical and chemical properties.  Both systems are characterized by confinement and large surface to volume ratio, which alter the chemistry of many processes relative to their bulk solution counterparts.

Excitations Dynamics Driving Electronic Correlations in Molecules and Solids

Abstract: Capturing the dynamics of electronic excitations in realistic systems containing more than a few electrons is one of the outstanding theoretical challenges. Dynamical quantum fluctuations mediate interactions among excited electrons (and holes), determining the material electronic structure and optoelectronic response. A predictive ab-initio theory is critical for understanding, predicting, and designing novel compounds with tailored (quantum) properties.

Metal Homeostasis at the host – pathogen interface: from nutritional immunity to nutritional intoxication

Abstract: Antibiotic resistance is a global health concern that causes over one million deaths worldwide. Understanding molecular mechanisms of bacterial pathogenesis and the innate immune response is critical for identifying new antimicrobial therapeutic approaches. My lab is interested in characterizing the underlying determinants of metal homeostasis with an eye toward creating new antimicrobial agents. One-third of the proteome is predicted to comprise metalloproteins.

From synchronization to chemical reaction superpositions

Abstract: Synchronization abounds in nature—why is it so hard to synchronize quantum systems? I will discuss this general question and its relationship to quantum coherence and exciton delocalization. I will then report new experiments that show how a molecular exciton state can launch two a superposition of two chemical reactions. Specifically, we study femtosecond proton transfer in a symmetric molecule with two identical reactant sites that are spatially apart.


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