Molecular-dynamics study of liquid water in strong laser fields

Effects of an intense laser field on liquid water are investigated by using classical molecular-dynamics computer simulations and a water model SPC-FP, which for the first time includes both flexible intramolecular bonds and instantaneous electronic polarization effects. Comparisons with the field-off system are made throughout. Under the influence of the strong external torque, both the liquid structure and the intramolecular geometry are distorted. These effects significantly change the dynamical behavior of the liquid compared with the field-off system. The presence of the intense electric field furthermore gives rise to a nonlinear response of the medium. We estimate the nonlinear index of refraction and give a brief discussion of self-focusing and supercontinuum generation.