Atomic processes in planetary nebulae

Abstract

Historically, Planetary Nebula research has been a ground for much development in atomic physics. In the last five years the combination of a generation of powerful observatories, the development of ever more sophisticated spectral modeling codes, and important efforts on mass production of high quality atomic data have led to important progress in our understanding of the atomic spectra of PNe. In this paper I review such progress, including identification of heavy species (beyond the iron peak elements), observations of hyperfine emission lines and analysis of isotopic abundances, fluorescent processes, and new techniques for diagnosing physical conditions based on recombination spectra. Finally I discuss the new trends on the research of atomic processes in PNe.