Observation of molecular orientation by the combination of electrostatic and nonresonant, pulsed laser fields

The orientation of polar molecules is demonstrated by the combination of electrostatic and nonresonant, nanosecond Nd:YAG laser fields. The orientation is probed by Coulomb exploding the molecules with a femtosecond laser pulse and detecting the fragment ions with the time-of-flight mass spectrometer. A significant asymmetry is observed in the signal magnitudes of the forward and the backward fragments, which is well explained in terms of the above-mentioned combined-fields scheme proposed by Friedrich and Herschbach [J. Phys. Chem. A 103, 10280 (1999)]. The degree of orientation is enhanced by increasing the peak intensity of the laser field and the magnitude of the electrostatic field, or by lowering the initial rotational temperature. The experimental results obtained are compatible with our numerical simulations. (C) 2003 American Institute of Physics.