Abstract

Use of superintense laser pulses with intensities comparable to the threshold intensity I_T ~ 10¹⁶ W/cm² for tunnel ionization of atoms gives us new possibilities for control of photoinduced reactions in molecules. For example, at moderate intensities; I ≪ I_T, electronic excitation of a molecule is insignificant, whereas at I ~ I_T strong excitation of electronic degrees of freedom takes place despite the nonresonant character of interaction. In this case the dynamics of nuclei are essentially different because they are governed not only by the potential-energy surface of the ground electronic state but also by potentials of other excited states. In particular, in sufficiently strong laser fields the lower term in the HCl⁺ molecule can become barrierless.¹

© 1993 Optical Society of America