  The goal of this white paper is to provide a snapshot of the data
availability and data needs primarily for the Ariel space mission, but also for
related atmospheric studies of exoplanets and brown dwarfs. It covers the
following data-related topics: molecular and atomic line lists, line profiles,
computed cross-sections and opacities, collision-induced absorption and other
continuum data, optical properties of aerosols and surfaces, atmospheric
chemistry, UV photodissociation and photoabsorption cross-sections, and
standards in the description and format of such data. These data aspects are
discussed by addressing the following questions for each topic, based on the
experience of the "data-provider" and "data-user" communities: (1) what are the
types and sources of currently available data, (2) what work is currently in
progress, and (3) what are the current and anticipated data needs. We present a
GitHub platform for Ariel-related data, with the goal to provide a go-to place
for both data-users and data-providers, for the users to make requests for
their data needs and for the data-providers to link to their available data.
Our aim throughout the paper is to provide practical information on existing
sources of data whether in databases, theoretical, or literature sources.
