FINITE-TEMPERATURE CHARACTERIZATION OF FERROCENE FROM FIRST-PRINCIPLES MOLECULAR-DYNAMICS SIMULATIONS

A first-principles molecular dynamics calculation of ferrocene [Fe(C5H5)(2)] at 300 K, based on the local density approximation, is presented. Kohn-Sham equations and forces on the atoms are obtained using the projector augmented wave technique. Frequencies and eigenmodes are derived by fitting a system of harmonic oscillators to the molecular dynamics trajectory. Frequency shifts for deuterated ferrocene [Fe(C5D5)(2), ferrocene-d(10)] and the corresponding eigenvectors are obtained by diagonalizing the dynamical matrix after renormalizing it according to the changed masses. Most experimental and theoretical frequencies agree to about 2.5% (or 20 wave numbers), with the exception of six modes for which a new assignment is proposed.