  X-ray diffraction (XRD) data and analysis for epitaxial iron selenide thin
films grown by pulsed laser deposition (PLD) are presented. The films contain
${\beta}$-FeSe and Fe$_7$Se$_8$ phases in a double epitaxy configuration with
the ${\beta}$-FeSe phase (001) oriented on the (001) MgO growth substrate.
Fe$_7$Se$_8$ simultaneously takes on two different epitaxial orientations in
certain growth conditions, exhibiting both (101)- and (001)- orientations. Each
of these orientations are verified with the presented XRD data. Additionally,
XRD data used to determine the PLD target composition as well as mosaic
structure of the ${\beta}$-FeSe phase are shown.
