Polarization effects on the ionization of molecules under picosecond and femtosecond laser excitation

We report experimental results related to the effect of laser polarization on the angular distributions of ions produced by the interaction of high-in tensity short laser pulse radiation with CS2, OCS, CO2 and CH3I. Using time -of-flight mass spectrometry and laser pulses of 200 fs at 800 and 400 nm a nd 500 fs at 248 and 497 nm we have observed strong laser-induced alignment of the singly and multiply charged fragments along and/or perpendicular to the direction of the electric field of the laser light. The dependence of the observed effects on laser wavelength and intensity has been studied. Th e results are shown to contribute to the elucidation of the alignment mecha nism.