Chemical Kinetics at the Single-Molecule Level

• Marcia Levitus ^[1]
  1. [1] Arizona State University

     Arizona State University

     Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 88, Nº 2, 2011, págs. 162-166
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • For over a century, chemists have investigated the rates of chemical reactions using experimental conditions involving huge numbers of molecules. As a consequence, the description of the kinetics of the reaction in terms of average values was good enough for all practical purposes. From the pedagogical point of view, such a description misses the stochastic nature of molecular behavior. Students can rarely connect the macroscopic kinetic behavior of a chemical reaction with its description at the molecular level. This article aims to bridge the gap between the macroscopic and microscopic interpretation of kinetic processes. This is not only important to understand the recently developed single-molecule physical chemistry field, but also to improve students’ understanding of the random nature of molecular behavior. Unimolecular processes are described at the molecular level in terms of their statistical behavior, and concepts such as the reaction lifetime are discussed in the context of both the ensemble and molecular descriptions. The article further describes simple simulations that can be used as classroom activities to strengthen student understanding of how the familiar monoexponential decay of a first-order reaction can be described in terms of a large number of random events at the molecular level.