CHIANTI – an atomic database for emission lines

IX. Ionization rates, recombination rates, ionization equilibria for the elements hydrogen through zinc and updated atomic data

¹ Department of Computational and Data Sciences, George Mason University, 4400 University Dr., Fairfax VA, 22030, USA e-mail: kdere@gmu.edu
² Artep, Inc. Ellicott City, MD, 21042; and Naval Research Laboratory, 4555 Overlook Ave. SW, Washington DC 20375-5320, USA e-mail: landi@poppeo.nrl.navy.mil
³ George Mason University, 4400 University Dr., Fairfax VA, 22030, USA and Naval Research Laboratory, 4555 Overlook Ave. SW, Washington DC 20375-5320, USA e-mail: pyoung@ssd5.nrl.navy.mil
⁴ Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK e-mail: G.Del-Zanna@damtp.cam.ac.uk
⁵ Dipartmento di Astronomia e Scienza dello Spazio, Universitá di Firenze, Largo E. Fermi 2, 50125 Firenze, Italy e-mail: landini@arcetri.astro.it
⁶ Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK e-mail: h.e.mason@damptp.cam.ac.uk

Received: 23 January 2009
Accepted: 8 March 2009

Abstract

Aims. The goal of the CHIANTI atomic database is to provide a set of atomic data for the interpretation of astrophysical spectra emitted by collisionally dominated, high temperature, optically thin sources.

Methods. A complete set of ground level ionization and recombination rate coefficients has been assembled for all atoms and ions of the elements of H through Zn and inserted into the latest version of the CHIANTI database, CHIANTI 6. Ionization rate coefficients are taken from the recent work of Dere (2007, A&A, 466, 771) and recombination rates from a variety of sources in the literature. These new rate coefficients have allowed the calculation of a new set of ionization equilibria and radiative loss rate coefficients. For some ions, such as and , there are significant differences from previous calculations. In addition, existing atomic parameters have been revised and new atomic parameters inserted into the database.

Results. For each ion in the CHIANTI database, elemental abundances, ionization potentials, atomic energy levels, radiative rates, electron and proton collisional rate coefficients, ionization and recombination rate coefficients, and collisional ionization equilibrium populations are provided. In addition, parameters for the calculation of the continuum due to bremsstrahlung, radiative recombination and two-photon decay are provided. A suite of programs written in the Interactive Data Language (IDL) are available to calculate line and continuum emissivities and other properties. All data and programs are freely available at http://wwwsolar.nrl.navy.mil/chianti