Spatial alignment of gas-phase polyatomic molecules by an intense laser field

Abstract

Angular distributions have been measured of Cl⁺ fragment ions resulting from dissociative ionization of polyatomic molecules CCl₄, CHCl₃ and CH₂Cl₂ induced by linearly polarized laser pulses of intensity 1013 W cm-2. Pronounced anisotropy is exhibited in all cases, with Cl⁺ detected mainly along the direction of the laser's polarization axis, indicative of field-induced spatial alignment of the precursor molecules. 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.