FIRST-PRINCIPLES MOLECULAR-DYNAMICS SIMULATIONS FOR NEUTRAL P-CHLORANIL AND ITS RADICAL-ANION

The neutral p-chloranil (2,3,5,6-tetrachloro-p-benzoquinone) and its r adical anion have been extensively studied using the Car-Parrinello pr ojector augmented wave method, which is an all-electron electronic str ucture method for first-principles molecular dynamics based on the loc al density approximation of density functional theory. Frequencies and eigenmodes are derived by fitting a system of harmonic oscillators to the molecular-dynamics trajectories. The dependence of the bond lengt hs and vibrational frequencies on the molecular ionicity is discussed, and the electron affinity, Coulomb repulsion, and the spin-splitting parameter of p-chloranil are also derived.