Theoretical Atomic Physics code development IV: LINES, A code for computing atomic line spectra

A new computer program, LINES, has been developed for simulating atomic line emission and absorption spectra using the accurate fine structure energy levels and transition strengths calculated by the (CATS) Cowan Atomic Structure code. Population distributions for the ion stages are obtained in LINES by using the Local Thermodynamic Equilibrium (LTE) model. LINES is also useful for displaying the pertinent atomic data generated by CATS. This report describes the use of LINES. Both CATS and LINES are part of the Theoretical Atomic PhysicS (TAPS) code development effort at Los Alamos. 11 refs., 9 figs., 1 tab

Theoretical atomic physics code development at Los Alamos

We have developed a set of computer codes for atomic physics calculations at Los Alamos. These codes can calculate a large variety of data with a minimum of effort on the part of the user. In particular, differential cross sections and electron impact coherence parameters can be readily obtained for arbitrary ions or atoms. Currently, the theory consists of non-relativistic Hartree-Fock structure calculations and non relativistic distorted wave approximation or first order many body theory collisional calculations. 12 refs., 2 figs., 5 tabs

Atomic and Molecular Data on Internet

International audienceGetting reliable atomic and molecular data for applications is a major challenge. In some instances, data can be obtained using analytical functions as proposed earlier. There are also some atomic and molecular codes available through the Internet, which can generate data online. However, the major trend currently is to download the information directly through the Internet. Web-based atomic and molecular databases have the advantage, when available, to readily provide reliable original data and possibly evaluated and/or recommended data. In this chapter, the current state of atomic and molecular and online calculation tools in early 2011 is described, with special focus on databases with a convenient user web-interface, as well as information distributed through data centrse

Supercomputers and atomic physics data

The advent of the supercomputer has dramatically increased the possibilities for generating and using massive amounts of detailed fine structure atomic physics data. Size, speed, and software have made calculations which were impossible just a few years ago into a reality. Further technological advances make future possibilities seem endless. The cornerstone atomic structure codes of R.D. Cowan have been adapted into a single code CATS for use on Los Alamos supercomputers. We provide a brief overview of the problem; and report a sample CATS calculation using configuration interaction to calculate collision and oscillator strengths for over 300,000 transitions in neutral nitrogen. We also discuss future supercomputer needs. 2 refs

Los Alamos opacity web page

The Los Alamos opacity data base is now available on the World Wide Web at http://t4.lanl.gov. The data base contains both the original Astrophysical Opacity Library distributed worldwide in the 1980`s (for historical reference) and the new improved opacities from the Light Element Detailed Configuration OPacity (LEDCOP) code. Users can access the opacity data using the multigroup opacity code TOPS to obtain Rosseland and Planck gray opacities, group mean opacities over selected energy ranges, the monochromatic absorption coefficients and the average ionization over a wide range of temperatures and densities. As described in this paper, these quantities are available for all of the elements presently on the data base and TOPS will provide the same quantities for any arbitrary mixture of these elements

New trends to access Access Atomic and Molecular Data

International audienceEasy access to reliable Atomic and Molecular Data and Particle Surface Interactions (AM/PSI) are essential in fusion energy research. New trend to provide AM/PSI data, is to combined with usual numerical databases, web calculation tools, to quickly compute missing data. In this scope, large scale calculations of excitation cross section by electron impact from Xe I to VIII have been performed and results made available on Internet

Theoretical atomic physics code development I: CATS: Cowan Atomic Structure Code

An adaptation of R.D. Cowan's Atomic Structure program, CATS, has been developed as part of the Theoretical Atomic Physics (TAPS) code development effort at Los Alamos. CATS has been designed to be easy to run and to produce data files that can interface with other programs easily. The CATS produced data files currently include wave functions, energy levels, oscillator strengths, plane-wave-Born electron-ion collision strengths, photoionization cross sections, and a variety of other quantities. This paper describes the use of CATS. 10 refs