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Showing 1 to 17 of 17 for “"Atomic processes"”.
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Atomic processes in nova shells
The unusual spectra of the spatially-resolved nova shells of DQ Her, T Aur and CP Pup are reviewed. Because calculations for these conditions have not been made, recombination models of HI, HeI and CNO from a neutral to a doubly ionized state were constructed. The models are described and the …
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Modelling line emission in the lower solar atmosphere
… is extended by successively including atomic processes which become more important further down. Firstly, the effects of higher density are added to the modelling of carbon and oxygen, to account for its effects on electron impact ionisation and dielectronic recombination. New …
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Calculated and measured line intensity ratios of singly and doubly ionized nitrogen atoms in hydrogen plasma
… by means of the Coulomb approximation. Atomic processes in a plasma are discussed, as well as two models (LTE and semi-coronal) which can be used to determine the line intensity ratios of subsequent ionization stages of the same element. Two derivations of line intensity ratio formulae …
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Theoretical Modelling and Characterisation of Concerted Tip and Surface Effects in NC-AFM
… that image molecules and surfaces with atomic precision. One such technique that has answered this call is Non-Contact Atomic Force Microscopy (NC-AFM), which has a very successful history of directly probing many atomic properties on a wide variety of systems. Interpretation of …
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Theoretical Modeling of Radiation-driven Atomic Kinetics of a Neon Photoionized Plasma
We report on a theoretical study on atomic kinetics modeling of a photoionized neon plasma at conditions relevant to laboratory experiments performed at the Z-machine in Sandia National Laboratories. We describe an atomic kinetics model and code, ATOKIN, that was developed and used to compute the …
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Observation and Characterization of Trends in the Ionization of the Warm Absorber Photoionized Plasma Experiment at Z
… low temperatures, wherein photon-driven atomic processes dominate over collisional processes in the atomic kinetics. The systems in which these exist are complex, and astrophysicists endeavoring to understand them utilize modeling software created to simulate the physics in such plasma …
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A determination of the formation rate of muonic hydrogen molecules in the MuCap experiment
… ultra pure hydrogen. Argon introduces additional atomic processes involving the muon, which affect the time spectra of muon decay electrons and capture neutrons. Fits to these data determine l_ppmu to a precision that is a significant improvement to the current world average. The main results are …
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A Multiscale Method for Simulating Fracture in Polycrystalline Metals
… particularly in simulating fundamental atomic mechanisms involved in the initiation and evolution of damage. Simulating fundamental material processes using first principles in physics strongly motivates the formulation of computational multiscale methods to link macroscopic failure to …
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Relationships between grain structure and stress in thin Volmer-Weber metallic films
… grain structure is in turn strongly dependent on atomic processes at the substrate surface at the onset of film growth. In this study, Kinetic Monte Carlo simulations were used to investigate the relationship between characteristics of the amorphous surface, nucleation and growth of islands, and …
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Characteristics of a Multipole Volume H-Plasma
… negative hydrogen ions are formed by volume processes. The ultimate object was to aid in understanding the mechanisms of volume H⁻ production, so enabling the output of this type of device to be optimised for use in the fusion programme. The study entailed the design and construction of one …
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Theoretical Studies of L-shell X-ray Line Polarization and M-shell X-ray Spectroscopic Emission from Highly Ionized Xenon Ions
… to laboratory-produced plasmas and underlying atomic processes. Xenon (Xe) radiation has been extensively studied for lithography applications and Xe gas-puffs have proven to be efficient radiation sources. Consequently, a new M-shell Xe non-LTE model was constructed using atomic database …
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Plasma-based CO₂ Conversion for Mars ISRU
… pressures compared to typical thermal conversion processes. Other benefits of Plasma-based conversion technologies include the compatibility with many feedstock gases, opening up possibilities for synthesizing other important chemicals in situ. Many plasma sources have been explored for CO₂ …
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Ultrafast Atomic Dynamics in Arbitrary Light Fields
… for simulating multielectron atoms and atomic ions in light fields of arbitrary complexity.<br/><br/>An ab initio R-matrix with time-dependence (RMT) theory for ultrafast atomic processes in arbitrarily polarised laser fields is described. The theory is applicable to multielectron atoms …
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Growth and Behaviors of InN/GaN Multiple Quantum Wells by Plasma-Assisted Molecular Beam Epitaxy
… RHEED intensity transient features with surface atomic processes such as the adsorption/desorption of metal species, the growth process was successfully monitored in situ. Also, at the high growth temperature, RHEED was successfully used to study the adsorption/desorption kinetics of indium …
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Multiscale models of the metalorganic vapor phase epitaxy process
… techniques for chemical vapor deposition processes, specifically metalorganic vapor phase epitaxy (MOVPE). The difficulty in creating an overall modeling strategy for the MOVPE process is that important processes occur on a wide range of length and time scales. Gas phase heat and mass …
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Theoretical and Experimental Studies of Radiation from High-Z Multiply Ionized L-shell Ions with Emphasis on X-ray Line Polarization
… intrinsically complicated nature. As such, the atomic physics associated with them, and corresponding application to high-energy-density (HED) plasmas is a complex and intricate problem. This dissertation intends to help in addressing this problem by providing a detailed theoretical and …
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X-ray Radiative Signatures Influenced by Nonthermal Effects in High-Energy-Density Laboratory Plasmas of Mid-Atomic-Number Z-pinches
… plasma environments with broad application to atomic physics, astrophysics, and HED laboratory physics, including inertial confinement fusion (ICF), making it an inimitable tool for interdisciplinary science. Spectroscopic examination of plasma radiation can yield robust information on plasma …