  We provide a set of atomic lines which are suitable for the description of
ultracool dwarf spectra from 10000 to 25000 \AA. This atomic linelist was made
using both synthetic spectra calculations and existing atlases of infrared
spectra of Arcturus and Sunspot umbra. We present plots, which show the
comparison of synthetic spectra and observed Arcturus and Sunspot umbral
spectra for all atomic lines likely to be observable in high resolution
infrared spectra.
