Quantum nuclear delocalization and its rovibrational fingerprints.

Abstract

Quantum mechanics dictates that nuclei must undergo some delocalization.In this work, emergence of quantum nuclear delocalization and its rovibrational fingerprints are discussed for the case of the van der Waals complex HHe3+.The equilibrium structure of HHe3+ is planar and T-shaped,one He atom solvating the quasi-linear He-H+-Hecore.The dynamical structure of HHe3+, in all of its bound states, isfundamentally different.As revealed by spatial distribution functions and nuclear densities, during thevibrations of the molecule the solvating He is not restricted to be in the planedefined by the instantaneously bent HHe3+ chomophore, but freely orbits the central proton, forming a three-dimensional torus around the HHe2+ chromophore.This quantum delocalization is observed for all vibrational states, the type ofvibrational excitation being reflected inthe topology of the nodal surfaces in the nuclear densities,showing, for example, that intramolecular bending involvesexcitation along the circumference of the torus.