Seminars arranged by CaSTL

Cooperative Function in Atomically Precise Nanoscale Assemblies

We use molecular design, tailored syntheses, intermolecular interactions, and selective chemistry to direct molecules into desired positions to create nanostructures, to connect functional molecules to the outside world, and to serve as test structures for measuring single or bundled molecules. Interactions within and between molecules can be designed, directed, measured, understood, and exploited at unprecedented scales. Such interactions can be used to form precise molecular assemblies, nanostructures, and patterns, and to control and to stabilize function.

Generation of Entanglement in Hybrid Quantum Dot/Plasmonic Systems with Ultrafast Laser Pulses

We propagate the quantum mechanical density matrix, including dephasing, spontaneous emission and dissipation to study systems composed of two, three or four quantum dots in proximity to a plasmonic system when exposed to an ultrafast optical pulse [1].  The plasmonic system could be a single metal nanoparticle or an array of metal nanoparticles or some other plasmonic structure and serves to enhance the local electric fields that arise due to the pulse.  We have previously studied a single quantum dot interacting with a plasmonic system and demonstrated how Fano resonances in tra

Novel Optical Properties of Small Metal Clusters

Small metal cluster systems have been investigated and have shown great potential for applications in catalysis, sensing, as well as for biophysical processes. This talk will discuss our recent nonlinear optical and time-resolved ultra-fast measurements of both gold and silver small metal clusters. The mechanism of the basic excitations in these smaller cluster systems will be discussed and compared to larger nanoparticles. The use of these clusters for applications in nonlinear optics as well as in phototherapy will be illustrated.

From water clusters to structural metabolomics: A chemical physicist’s journey to the heart of contemporary chemistry with cryogenic ion photofragmentation mass spectrometry

The coupling between ambient ionization sources, developed for mass spectrometric analysis of biomolecules, and cryogenic ion processing, originally designed to study interstellar chemistry, creates a new and general way to capture transient chemical species and elucidate their structures with optical spectroscopies.  Advances in non-linear optics over the past decade allow single-investigator, table top lasers to access radiation from 550 cm-1 in the infrared to the vacuum ultraviolet.

Unique properties of photon-assisted catalysis at metal nanocrystal surfaces

Photon driven chemical reactions at metal surfaces have been studied for over forty years with a focus on non-adiabatic, electron driven chemical processes in the context of controlling reaction selectivity. A majority of these studies have been executed on metal single crystals, where surface electric fields have small magnitudes and chemistry is typically driven through substrate-mediated excitation of adsorbate-metal bonds that competes with hot charge carrier diffusion into the bulk.

Numerical studies of the scattering of light from, and its transmission through, two-dimensional randomly rough surfaces

Calculations of the scattering of light from, and its transmission through, two-dimensional randomly rough surfaces are computationally intensive, and are still often carried out by means of small-amplitude perturbation theory, the Kirchhoff approximation, or the small slope approximation.  However, accurate approaches to the solution of such problems are needed in a variety of contexts, and searches for such approaches are an active area of research in computational electrodynamics.

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