CHIANTI - an atomic database for emission lines - I. Wavelengths greater than 50 Å

CHIANTI consists of a critically evaluated set of atomic data and transition probabilities necessary to calculate the emission line spectrum of astrophysical plasmas. The data consist of atomic energy levels, atomic radiative data such as wavelengths, weighted oscillator strengths and A values, and electron collisional excitation rates. A set of programs that use these data to calculate the spectrum in a desired wavelength range as a function of temperature and density is also provided. A suite of programs has been developed to carry out plasma diagnostics of astrophysical plasmas. The state-of-the-art contents of the CHIANTI database will be described and some of the most important results obtained from the use of the CHIANTI database will be reviewed.