  The IR- and Raman-active phonon frequencies, as well as the elastic constants
of orthorhombic GeSe, were calculatedas a function of hydrostatic pressure
using the method of density functional in the ABINIT software package.
Comparison with the published results of theoretical calculations and
experimental data of the pressure dependence of Raman-active phonons has been
carried out. Our calculations show that at a pressure of about 29 GPa the
crystal structure of GeSe undergoes a continuous transition from simple
orthorhombic to base-centered orthorhombic lattice.
