Controlling intramolecular hydrogen migration by asymmetric laser fields: the water case.

Abstract

Hydrogen and deuterium intramolecular migration in water s isotopomer dications has been found to depend on the wavelength of the laser used for the excitation. This is imprinted in H2+ and D2+ fragment ions observation in the mass spectra induced by single color fs laser irradiation with 800 nm ≤λ≤ 1570 nm. Based on these findings, experiments with ω/2ω asymmetric laser fields (1400/700 nm) have been performed. The dissociation channels of the dications exhibit different dependence on the phase between the ω and 2ω components of the field thus offering an ability for controlling the fragmentation. For the interpretation of these observations, a tunneling mechanism is invoked.