Dynamic alignment of CH3I by strong picosecond laser pulses

The angular distributions of the fragment ions of methyl iodide (CH3I) irradiated by strong 35 ps laser pulses have been recorded at different wavelengths using a time-of-flight mass spectrometer. From the analysis of the angular distributions it is concluded that the singly and the transient doubly and triply charged parent ions are aligned by the laser beam (dynamic alignment). Under the present experimental conditions the CH3I is adiabatically aligned. Molecular alignment has been observed for all the laser wavelengths (1064, 532, 355 and 266 nm) used and it is found to be more efficient at the longer one, while reaches saturation for laser intensities higher than 1014 W/cm2.