title: Vibron-phonon coupling strength in a finite size lattice of H-bonded peptide units.
abstract: An attempt is made to measure the vibron-phonon coupling strength in a finite size lattice of H-bonded peptide units. Within a finite temperature density matrix approach, we compare separately the influence of both the vibron-phonon coupling and the dipole-dipole interaction on the coherence between the ground state and a local one-vibron state. Due to the confinement, it is shown that the vibron-phonon coupling yields a series of dephasing-rephasing mechanisms that prevents the coherence to decay. Similarly, the dipole-dipole interaction gives rise to quantum recurrences for specific revival times. Nevertheless, intense recurrences are rather rare events so that the coherence behaves as a random variable whose most probable value vanishes. By comparing the degree of the coherence for each interaction, a critical coupling chi*(L) is defined to discriminate between the weak and the strong coupling limits. Its size dependence indicates that the smaller the lattice size is, the weaker the vibron-phonon coupling relative to the dipole-dipole interaction is.
authors.affiliation: Institut UTINAM, Université de Franche-Comté, CNRS UMR 6213, 25030 Besançon Cedex, France. vincent.pouthier@univ-fcomte.fr
authors.forename: Vincent
authors.initials: V
authors.lastname: Pouthier
mesh_terms: D001665:Binding Sites; D003198:Computer Simulation; D006860:Hydrogen Bonding; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry*; D017785:Photons; D011485:Protein Binding; D013314:Stress, Mechanical
chemical_list: D010455:Peptides