SPATIAL ALIGNMENT OF GAS-PHASE POLYATOMIC-MOLECULES BY AN INTENSE LASER FIELD

Angular distributions have been measured of Cl+ fragment ions resultin g from dissociative ionization of polyatomic molecules CCl4, CHCl3 and CH2Cl2 induced by linearly polarized laser pulses of intensity 10(13) W cm(-2). Pronounced anisotropy is exhibited in all cases, with Cl+ d etected mainly along the direction of the laser's polarization axis, i ndicative of field-induced spatial alignment of the precursor molecule s. The directional properties of the average linear polarizability of the precursors appear to play a key role in determining the extent to which such alignment occurs.