title: Quantum confinement of the covalent bond beyond the Born-Oppenheimer approximation.
abstract: Dirichlet boundary conditions with different symmetries, spherical and cylindrical impenetrable surfaces, are imposed on the covalent electron pair of a molecular bond. Accurate results for different observable like energy and interparticle distances are calculated using quantum Monte Carlo methods beyond the Born-Oppenheimer approximation. The spherical confinement induces a raise in the bond energy and shortens the internuclear distances even for a relatively soft confinement. When cylindrical symmetry is considered, similar qualitative behavior is observed though only the electrons are confined. A compression followed by a relaxation process of the confined bond is shown to induce a vibrationally excited state. Finally, a brief qualitative discussion based on a simplified picture of the role of compression/relaxation cycles in enzyme catalysis is given.
authors.affiliation: Departamento de Fı́sica, Facultad de Ciencias, Universidad de Córdoba, E-14071 Córdoba, Spain. fa1sarua@uco.es
authors.forename: A
authors.initials: A
authors.lastname: Sarsa
authors.forename: J M
authors.initials: JM
authors.lastname: Alcaraz-Pelegrina
authors.forename: C
authors.initials: C
authors.lastname: Le Sech
authors.forename: S A
authors.initials: SA
authors.lastname: Cruz
mesh_terms: D009010:Monte Carlo Method; D011789:Quantum Theory; D013499:Surface Properties