# 5.2. ALM: Output files¶

• PREFIX.pattern_HARMONIC, PREFIX.pattern_ANHARM?
In these files, displacement patterns are printed in units of $$\boldsymbol{e}_{x,y,z}$$. These files are created when MODE = suggest. Patterns for anharmonic force constants are printed only when NORDER > 1.
• PREFIX.fcs
Harmonic and anharmonic force constants in Rydberg atomic units. In the first section, only symmetry-reduced force constants are printed. All symmetry-related force constants are shown in the following section with the symmetry prefactor ($$\pm 1$$). Created when MODE = fitting.
• PREFIX.xml
An XML file containing the necessary information for performing phonon calculations. The files can be read by anphon using the FCSXML-tag. Created when MODE = fitting.