In this work we have performed an extensive high pressure study of the condensed phases
of pyridine by Raman and IR spectroscopy. We have evidenced three different polymorphs,
two crystalline, and one glassy and established the pressure conditions in which they exist
as stable or metastable phases by several compression/decompression experiments both
on annealed and not annealed samples. Crystallization and phase transitions are found to
be kinetically driven. The vibrational spectra are extremely complex due to the low symmetry …