Atomic symbols are set by this tag. This tag is not essential for
phonon calculation and is used by mode2anime.rb. Required number of
names are determined by POSCAR file. If two distinguished ion species
are written in POSCAR, you need to set two names. However, if atom
names are written in line 6 of POSCAR, ATOM_NAME
tag is
ignored and the POSCAR information takes priority.
example
ATOM_NAME = Sn O