JILA Auditorium

New Insights into the Impact of Water on the Reactivity Of Criegee Intermediate Reactions

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Abstract: Biogenic emissions contribute significantly to the composition and chemistry of the troposphere, with vegetation being the main source of volatile alkenes. For example, isoprene is emitted by plants during photosynthesis and is one of the most abundant organic compounds released into the atmosphere: around 500 Tg of isoprene is emitted annually and forms the largest fraction of non-methane hydrocarbon emissions. The dominant mechanisms for the atmospheric removal of alkenes are reactions with the OH radical and ozone.

Following and controlling nanoscale formation and function of bottom-up assembled materials

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Abstract: Short-range-interacting particles can in principle crystallize via so-called non-classical pathways invoking a metastable liquid intermediate, yet non-equilibrium gelation often occurs before a metastable liquid can form. Using in situ X-ray scattering, we nevertheless watch electrostatically stabilized colloidal semiconducting nanocrystals self-assemble into long-range-ordered superlattices via this non-classical pathway and show how the pathway increases the rate of crystallization over that of direct crystallization from the colloidal phase.

How driving force and charge transfer distance control free charge generation at donor/acceptor interfaces

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Abstract:  I present evidence that electron-transfer in model organic photovoltaic blends can be modeled as a competition between short and long-range electron transfer events, each described by a Marcus parabola having different reorganization energies for the most localized charge-transfer (CT) state and the mobile free charge (CT) state.

Spatial and Temporal Dynamics of Excitons in Van der Waals Heterostructures

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Abstract: Atomically thin van der Waals crystals like graphene and transition metal dichalcogenides allow for the creation of arbitrary, atomically precise heterostructures simply by stacking disparate monolayers without the constraints of covalent bonding or epitaxy. While these are commonly described as nanoscale LEGO blocks, many intriguing phenomena have been discovered in the recent past that go beyond this simple analogy.

Developing current and next generation physics assessments

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Abstract: The ability to measure what students are learning (or not) is a crucial component of crafting effective learning environments. In particular, low-stakes, standardized diagnostic assessments can provide a valuable tool for tracking student learning over time and between instructional approaches to identify effective strategies that improve students' understanding of core physics content.

Ergodicity breaking in quantum dynamics

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When can isolated many body quantum systems fail to go to equilibrium under their own dynamics, and how robust can this 'ergodicity breaking’ be? This question has been a central theme of research in quantum dynamics and statistical mechanics over the past decade, and I will share with you some highlights, focusing on three key developments: many body localization, dynamics with multipolar symmetries, and dynamics with higher form symmetries. I will present the rich and exotic phenomena that arise in these three regimes, and how they may be realized experimentally.

Nanoscale Imaging and Nano-FTIR Spectroscopy of Surface Nano-Thick Polydopamine Films: What is the Role of Deposition Time and Substrate Material?

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Abstract: Polydopamine (PDA) is a widely employed anchoring layer across various applications. Despite its straightforward preparation, PDA's utility is restricted due to its notable chemical and topological variability. Understanding the formation process and physicochemical characteristics of the formed confluent layers, as well as the present adherent nanoaggregates [1 – 3], on a nanoscale level is essential for expanding the applications of PDA.