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Related papers: Non-LTE Model Atom Construction

200 papers

Non-LTE radiative transfer is a key tool for modern astrophysics: it is the means by which many key synthetic observables are produced, thus connecting simulations and observations. Radiative transfer models also inform our understanding of…

Solar and Stellar Astrophysics · Physics 2025-11-12 Christopher M. J. Osborne , Alexander Sannikov

Aluminium plays a key role in studies of the chemical enrichment of the Galaxy and of globular clusters. However, strong deviations from LTE (non-LTE) are known to significantly affect the inferred abundances in giant and metal-poor stars.…

Solar and Stellar Astrophysics · Physics 2017-11-28 Thomas Nordlander , Karin Lind

Statistical learning algorithms are finding more and more applications in science and technology. Atomic-scale modeling is no exception, with machine learning becoming commonplace as a tool to predict energy, forces and properties of…

Chemical Physics · Physics 2020-12-09 Félix Musil , Michele Ceriotti

We perform non-LTE calculations of lithium in late-type stars for a wide range of stellar parameters, including quantum mechanical cross-sections for collisions with neutral hydrogen and the negative hydrogen ion. Non-LTE abundance…

Solar and Stellar Astrophysics · Physics 2015-05-13 K. Lind , M. Asplund , P. S. Barklem

The Embedded-Atom Model (EAM) provides a phenomenological description of atomic arrangements in metallic systems. It consists of a configurational energy depending on atomic positions and featuring the interplay of two-body atomic…

Mathematical Physics · Physics 2021-09-01 Laurent Bétermin , Manuel Friedrich , Ulisse Stefanelli

We present the first non-LTE model atmospheres for neutron stars (NS). We study their structure and NLTE effects on the emergent thermal radiation of old isolated NS.

Astrophysics · Physics 2007-05-23 K. Werner , J. Deetjen

Modelling quantum devices is to find a model according to quantum theory that can explain the result of experiments in a quantum device. We find that usually we cannot correctly identify the model describing the actual physics of the device…

Quantum Physics · Physics 2019-10-08 Hang Ren , Ying Li

In the aim of determining accurate iron abundances in stars, this work is meant to empirically calibrate H-collision cross-sections with iron, where no quantum mechanical calculations have been published yet. Thus, a new iron model atom has…

Solar and Stellar Astrophysics · Physics 2016-09-30 Rana Ezzeddine , Thibault Merle , Bertrand Plez

In this paper we discuss numerical methods and algorithms for the solution of NLTE stellar atmosphere problems involving expanding atmospheres, e.g., found in novae, supernovae and stellar winds. We show how a scheme of nested iterations…

Astrophysics · Physics 2011-06-02 P. H. Hauschildt , E. Baron

Carbon abundances in late-type stars are important in a variety of astrophysical contexts. However C i lines, one of the main abundance diagnostics, are sensitive to departures from local thermodynamic equilibrium (LTE). We present a model…

Solar and Stellar Astrophysics · Physics 2019-04-24 A. M. Amarsi , P. S. Barklem , R. Collet , N. Grevesse , M. Asplund

Various available codes for NLTE modeling and analysis of hot star spectra are reviewed. Generalizations of standard equations of kinetic equilibrium and their consequences are discussed.

Solar and Stellar Astrophysics · Physics 2016-07-27 Jiří Kubát

Context. B-type supergiants are versatile tools to address various astrophysical topics, ranging from stellar atmospheres over stellar and galactic evolution to the cosmic distance scale. Aims. A hybrid non-LTE approach - line-blanketed…

Solar and Stellar Astrophysics · Physics 2023-01-10 D. Weßmayer , N. Przybilla , K. Butler

Sphere packings are essential to the development of physical models for powders, composite materials, and the atomic structure of the liquid state. There is a strong scientific need to be able to assess the fit of packing models to data,…

Methodology · Statistics 2009-10-31 Jeffrey Picka

We define a formal framework for reasoning about linear-time properties of quantum systems in which quantum automata are employed in the modeling of systems and certain closed subspaces of state (Hilbert) spaces are used as the atomic…

Quantum Physics · Physics 2011-01-04 Mingsheng Ying , Yangjia Li , Nengkun Yu , Yuan Feng

We present non-Local Thermodynamic Equilibrium (non-LTE) calculations for neutral carbon spectral line formation, carried out for a grid of model atmospheres covering the range of late-type stars. The results of our detailed calculations…

Astrophysics · Physics 2015-06-24 Damian Fabbian , Martin Asplund , Mats Carlsson , Dan Kiselman

Decomposition of text into atomic propositions is a flexible framework allowing for the closer inspection of input and output text. We use atomic decomposition of hypotheses in two natural language reasoning tasks, traditional NLI and…

Computation and Language · Computer Science 2025-03-10 Neha Srikanth , Rachel Rudinger

The concept of basic chemical models is introduced, which is new from the standpoint of the physics of nonideal atomic plasma. This concept is based on the requirement of full conformity of the expression for free energy in the chemical…

Plasma Physics · Physics 2015-06-26 A. L. Khomkin , I. A. Mulenko , A. S. Shumikhin

Nonlinear spectroscopy employs a series of laser pulses to interrogate dynamics in large interacting many-body systems, and has become a highly successful method for experiments in chemical physics. Current quantum optical experiments…

Quantum Physics · Physics 2016-10-19 Frank Schlawin , Manuel Gessner , Shaul Mukamel , Andreas Buchleitner

MD simulations of the non-equilibrium melting of aluminum are performed both with and without accounting of the electronic subsystem. A continuum model of melting is purposed basing on the obtained MD results, in which the current phase…

Materials Science · Physics 2015-12-25 Alexander E. Mayer , Vasiliy S. Krasnikov

The atomic lensing model has been proposed as a promising method facilitating atom-counting in heterogeneous nanocrystals [KHW van den Bos et. al, Phys. Rev. Lett. 116 (2016) 246101] Here, image simulations will validate the model, which…

Materials Science · Physics 2019-02-18 K. H. W. van den Bos , L. Janssens , A. De Backer , P. D. Nellist , S. Van Aert