1 Introduction

Over the past several years, the line broadening theory developed by Anstee & O'Mara ([1991]) has been used to compute line broadening cross-sections due to hydrogen collisions for a range of transitions between general states with given effective principal quantum numbers using Coulomb wavefunctions. For s-p and p-s transitions these calculations were presented by Anstee & O'Mara ([1995]), for p-d and d-p by Barklem & O'Mara ([1997]), and for d-f and f-d transitions by Barklem et al. ([1998]).

More recently, the theory has been developed further to allow the calculation of broadening data for specific lines of singly ionised elements (Barklem & O'Mara [1998]). It was found that the interatomic interactions could not be considered in the same general way as for neutrals, and hence each line needs to be considered individually. This has been done for astrophysically important lines of the alkaline earth elements, and results have been presented by Barklem & O'Mara ([1998,2000]).

The goal of the work presented in this paper was to produce a list of data based on these calculations for a large number of spectral lines. We aimed in particular to include the majority of strong lines in cool stars, where this broadening mechanism is most important. We have also incorporated this data into the Vienna Atomic Line Database (Kupka et al. [1999]) and examined statistically the impact of the new list.