DYNAMICS OF A LASER-DRIVEN MOLECULAR MOTOR

Using molecular dynamics methods, we have simulated several model grap hite nanometer-scale laser driven motors. To our knowledge, this is th e first study of laser excitation of a nanometer-scare device. The mot ors consisted of two concentric graphite cylinders (shaft and sleeve) with one positive and one negative electric charge attached to the sha ft; rotational motion of the shaft was induced by applying one or some times two oscillating laser fields. The shaft cycled between periods o f rotational pendulum-like behavior and unidirectional rotation (motor -like behavior). The motor on and off times strongly depended on the m otor size, field strength and frequency, and relative location of the attached positive and negative charges. In addition, the two-laser sim ulations showed much larger motor on times and more stable rotation th an one-laser simulations. A mathematical model of the overall process was obtained by employing computational neural networks (CNNs). A CNN was able to 'learn' the mapping from size, charge position, frequency, and strength of the electric field to the motor on and off times. Thi s multidimensional, nonlinear mapping was determined to within an aver age accuracy of 2% and could be used to determine initial parameters t hat would lead to better overall performance of the nanomotor.