2011/07/13 by Astrid S. de Wijn · 21 citations
Chemistry · Physics and Astronomy · #Chemical physics #Chemistry #Classical mechanics #Composite material #Computational chemistry #Coupling (piping) #Degrees of freedom (physics and chemistry) #Diffusion #Graphite #Materials science #Mechanical and Optical Resonators #Mechanics #Molecular dynamics #Nonlinear system #Observable #Physics #Quantum chaos and dynamical systems #Quantum mechanics #Spectroscopy and Quantum Chemical Studies #Thermal #Thermodynamics #cond-mat.mes-hall #nlin.CD
paper · pdf · doi:10.1103/physreve.84.011610
published in Physical Review E 84(1), 011610 (American Physical Society) · 13 pages, 7 figures, 1 table
arxiv created 2011/07/13 · openalex publication_date 2011/07/18 · arxiv updated 2011/07/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In this paper, the chaotic internal degrees of freedom of a benzene molecule adsorbed on a graphite substrate, their interplay with thermal noise, and their effects on the diffusion and drift are investigated analytically by making use of the presence of two different time scales as well as by molecular-dynamics simulations. The effects of thermal noise are investigated, and it is found that noise does not significantly alter the dynamics of the internal degrees of freedom yet does affect the friction and diffusion of the center of mass. Qualitative and quantitative theoretical predictions for the friction and diffusion of the molecule on the substrate are made and are compared to molecular-dynamics simulations. Contributions to the friction and diffusion from the finite heat bath as well as the slow dynamics of the center of mass are formally identified. It is shown that the torsion in benzene, which dominates the nonlinear coupling, significantly affects the friction of the molecule on the surface. The results compare favorably with recent results from He-neutron spin echo experiments on this system. Based on the analytical and numerical results, some suggestions are made for experimental conditions under which the effects of internal degrees of freedom might be observable.