QUASI-HARMONIC LATTICE-DYNAMICS - THE PHASE-DIAGRAM OF BENZENE

We present a quasi harmonic lattice dynamics calculation for the cryst al structure and the phonon frequencies of orthorhombic and monoclinic benzene as a function of pressure and temperature. We employ a site-s ite potential model including Coulombic interactions, which were found necessary to obtain the correct low pressure phase. The calculations agree with the measurements in both phases and reproduce very well the experimental phase diagram. When applicable, quasi harmonic lattice d ynamics is an accurate and extremely efficient method, which promises to outperform molecular dynamics and Monte Carlo simulations.