Genetic algorithms applied to the control of molecular dynamics.

The dynamics of atoms and molecules under time-dependent external fields have been studied extensively in recent decades, due to experimental advances in the production of intense femtosecond-scale laser pulses. Thus, with the proper knowledge of the modulation of these pulses, several intra and intermolecular processes, such as vibrational excitation, fotodissociation, and even chemical reactions, can be controlled. Among the many possible methods for optimizing the temporal evolution of the initial state density to a desired quantum state configuration, genetic algorithms are among those that most efficiently map the configuration space, looking for global maxima and minima. The space to be mapped by the genetic algorithm consists of numerical solutions of the time-dependent Schrödinger equation due to the presence of an interaction field-dependent Hamiltonian. In the present work, a temporal propagation algorithm was implemented to simulate the vibrational excitation of the OH bond of water through femtosecond laser pulses in the infrared. And a genetic algorithm for the optimization of these pulses was also studied. Measurement techniques used in FELs, such as pump-probe measurements, can benefit from similar algorithms.