Publications by authors named "P Vashishta"

High electric fields can significantly alter catalytic environments and the resultant chemical processes. Such fields arise naturally in biological systems but can also be artificially induced through localized nanoscale excitations. Recently, strong field excitation of dielectric nanoparticles has emerged as an avenue for studying catalysis in highly ionized environments, producing extreme electric fields.

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  • The oscillatory retinal neuron (ORN) technology facilitates in-sensor cognitive image computing without relying on external power sources.
  • Its operation hinges on photoinduced negative differential resistance (NDR) at the graphene/silicon interface, which converts optical signals into voltage oscillations, though the underlying optoelectronic mechanism of NDR is not fully understood.
  • Recent simulations reveal that the combination of band alignment and charge transfer rates of excited carriers affects NDR, paving the way for better design of ORN devices for image computing in AI applications.
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  • Surface charges are crucial in determining the catalytic properties of nanomaterials, but studying their dynamics at the nanoscale is difficult due to varying length and time scales.
  • This study utilizes reaction nanoscopy to visualize charge dynamics on individual SiO nanoparticles with femtosecond and nanometer resolution, revealing how surface charges redistribute over time.
  • The research enhances our understanding of how surface charges affect chemical bonding on a nanoscale level, which could have significant implications for renewable energy and advanced healthcare innovations.*
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High-temperature flexible polymer dielectrics are critical for high density energy storage and conversion. The need to simultaneously possess a high bandgap, dielectric constant and glass transition temperature forms a substantial design challenge for novel dielectric polymers. Here, by varying halogen substituents of an aromatic pendant hanging off a bicyclic mainchain polymer, a class of high-temperature olefins with adjustable thermal stability are obtained, all with uncompromised large bandgaps.

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Vibrational spectroscopy allows us to understand complex physical and chemical interactions of molecular crystals and liquids such as ammonia, which has recently emerged as a strong hydrogen fuel candidate to support a sustainable society. We report inelastic neutron scattering measurement of vibrational properties of ammonia along the solid-to-liquid phase transition with high enough resolution for direct comparisons to ab-initio simulations. Theoretical analysis reveals the essential role of nuclear quantum effects (NQEs) for correctly describing the intermolecular spectrum as well as high energy intramolecular N-H stretching modes.

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