fizyka: Quantum reflection

Evidence: 100 • authority: 72

Quantum reflection is a uniquely quantum phenomenon in which an object, such as a neutron or a small molecule, reflects smoothly and in a wavelike fashion from a much larger surface, such as a pool of mercury. A classically behaving neutron or molecule will strike the same surface much like a thrown ball, hitting only at one atomic-scale location where it is either absorbed or scattered. Quantum reflection provides a powerful experimental demonstration of particle-wave duality, since it is the extended quantum wave packet of the particle, rather than the particle itself, that reflects from the larger surface. It is similar to reflection high-energy electron diffraction, where electrons refl…

Evidence: 42 • authority: 90

The adsorption of fluorinated dopants at the surface of 5CB: a neutron reflection study. The adsorption of dopants at the surface of 5CB has been studied using neutron reflection. The dopants were versions of 11OCB with partly fluorinated chains, and the 5CB was interfaced with air or with silica treated with fluorocarbon or hydrocarbon coatings. At the air interface, the F17-11OCB adsorbed homeotropically, and the amount increased on cooling into the nematic phase of 5CB. At low temperatures, the adsorption from the nematic phase appeared to saturate at a bilayer. At the solid interfaces, there was some evidence for a thin planar layer at the surface, but most of the adsorbed dopant was in…

Evidence: 35 • authority: 92

Synthesis, crystal structure at 100 K, Hirshfeld surface analysis, DFT calculations, antioxidant evaluation and molecular docking study of N,N'-diformohydrazide.. N,N'-Diformohydrazide was synthesized in 89% yield from hydrazine hydrate and formic acid and characterized by single-crystal X-ray diffraction at 100 K. The compound crystallizes in the monoclinic space group P2 1 /n. The molecule is planar, and the crystal packing is dominated by N-H···O and C-H···O hydrogen bonds that build corrugated two-dimensional sheets, with H···O contacts identified as the major contributor in Hirshfeld surface analysis. DFT calculations at the ωB97X-D/6-311 + + G(d, p) level reveal a large HOMO-LUMO gap…

Evidence: 35 • authority: 72

A neutron is a subatomic particle, symbol n or n0, that has no electric charge, and a mass slightly greater than that of a proton. The neutron was discovered by James Chadwick in 1932, leading to the discovery of nuclear fission in 1938, the first self-sustaining nuclear reactor (Chicago Pile-1, 1942), and the first nuclear weapon (Trinity, 1945). Neutrons are found, together with a similar number of protons, in the nuclei of atoms. Atoms of a chemical element that differ only in neutron number are called isotopes. Free neutrons are produced copiously in nuclear fission and fusion. They are a primary contributor to the nucleosynthesis of chemical elements within stars through fission, fusio…