Entanglement of vibrational modes in triatomic molecules

The properties of dynamical entanglement of anharmonic stretches in triatomic molecules H2O, O3, C2H2, C2D2, and SO2 are studied in terms of the reduced-density von Neumann entropy with various initial states. It is demonstrated that the maximal entropy of an initial state with local-mode character is smaller than that with normal-mode character. A mean entanglement, defined by average over time, is used to describe the influence of the normal-to-local transition on the behavior of entanglement. It is shown that the mean entanglement exhibits a maximum near the position of the normal-to-local transition.