Observation of Quantum Effects in sub Kelvin Cold Reactions

There has been a long-standing quest to observe chemical reactions at low temperatures where reaction rates and pathways are governed by quantum mechanical effects. So far this field of Quantum Chemistry has been dominated by theory. The difficulty has been to realize in the laboratory low enough collisional velocities between neutral reactants, so that the quantum wave nature could be observed. We report here the first realization of merged neutral supersonic beams, and the observation of clear quantum effects in the resulting reactions. We observe orbiting resonances in the Penning ionization reaction of argon and molecular hydrogen with metastable helium leading to a sharp increase in the absolute reaction rate in the energy range corresponding to a few degrees kelvin down to 10 mK. Our method is widely applicable to many canonical chemical reactions, and will enable a breakthrough in the experimental study of Quantum Chemistry

Optical diagnostics for turbulent and multiphase flows: Particle image velocimetry and photorefractive optics

This report summarizes the work performed under the Sandia Laboratory Directed Research and Development (LDRD) project ``Optical Diagnostics for Turbulent and Multiphase Flows.`` Advanced optical diagnostics have been investigated and developed for flow field measurements, including capabilities for measurement in turbulent, multiphase, and heated flows. Particle Image Velocimetry (PIV) includes several techniques for measurement of instantaneous flow field velocities and associated turbulence quantities. Nonlinear photorefractive optical materials have been investigated for the possibility of measuring turbulence quantities (turbulent spectrum) more directly. The two-dimensional PIV techniques developed under this LDRD were shown to work well, and were compared with more traditional laser Doppler velocimetry (LDV). Three-dimensional PIV techniques were developed and tested, but due to several experimental difficulties were not as successful. The photorefractive techniques were tested, and both potential capabilities and possible problem areas were elucidated

Grain Yield and Nutrient Uptake of Rice as Influenced by the Nano Forms of Nitrogen and Zinc

An experiment was conducted at college farm, College of Agriculture, Rajendranagar, Hyderabad, Telangana, in Sandy loam soils during rabi, 2020 to study the effect of nano nitrogen and nano zinc on the yield and nutrient uptake of rice (Oryza sativa. L). The experiment was carried out in randomised block design with 10 treatments and 3 replications. Results revealed that application of 50% conventional nitrogen fertilizer + foliar spray of 4 ml L-1 nano nitrogen at tillering and before panicle initiation stage + foliar spray of 2 ml L-1 nano zinc at tillering and before panicle initiation stage (T10) significantly increased the  grain yield (6810 kg ha-1) and uptake of nitrogen (147.7 kg ha-1), phosphorous (30.0 kg ha-1), potassium (137.9 kg ha-1) and zinc (367 kg ha-1) which were on par with (T9) application of 50% conventional nitrogen fertilizer + foliar spray of 4 ml L-1 nano nitrogen at tillering and before panicle initiation stage

Directly probing anisotropy in atom-molecule collisions through quantum scattering resonances

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Observation of the isotope effect in sub-kelvin reactions

Quantum phenomena in the translational motion of reactants, which are usually negligible at room temperature, can dominate reaction dynamics at low temperatures. In such cold conditions, even the weak centrifugal force is enough to create a potential barrier that keeps reactants separated. However, reactions may still proceed through tunnelling because, at low temperatures, wave-like properties become important. At certain de Broglie wavelengths, the colliding particles can become trapped in long-lived metastable scattering states, leading to sharp increases in the total reaction rate. Here, we show that these metastable states are responsible for a dramatic, order-of-magnitude-strong, quantum kinetic isotope effect by measuring the absolute Penning ionization reaction rates between hydrogen isotopologues and metastable helium down to 0.01 K. We demonstrate that measurements of a single isotope are insufficient to constrain ab initio calculations, making the kinetic isotope effect in the cold regime necessary to remove ambiguity among possible potential energy surfaces