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 radical anion are extensively studied by means of the Car-Parrinello projector augmented wave method which is an all-electron electronic structure method, for first-principles molecular dynamics based on the local density approximation of the density functional theory. Frequencies and eigenmodes are derived by fitting a system of harmonic oscillators to the molecular dynamics trajectories. Bond lengths and vibrational frequencies dependence on molecular ionicity are presented. Electron affinity, Coulomb repulsion and the spin-splitting parameter of p-chloranil are also estimated.