The ExoMol database: molecular line lists for exoplanet and other hot
  atmospheres
  The ExoMol database (www.exomol.com) provides extensive line lists of
molecular transitions which are valid over extended temperatures ranges. The
status of the current release of the database is reviewed and a new data
structure is specified. This structure augments the provision of energy levels
(and hence transition frequencies) and Einstein $A$ coefficients with other key
properties, including lifetimes of individual states, temperature-dependent
cooling functions, Land\'e $g$-factors, partition functions, cross sections,
$k$-coefficients and transition dipoles with phase relations. Particular
attention is paid to the treatment of pressure broadening parameters. The new
data structure includes a definition file which provides the necessary
information for utilities accessing ExoMol through its application programming
interface (API). Prospects for the inclusion of new species into the database
are discussed.
