Angular distributions of the products of dissociative ionization of molecules by intense laser fields

Abstract

Large dipole moments can be induced in molecules by intense, linearly polarized light fields. Such dipole moments exert large torques on molecules, which can swamp rotational motion, and give rise to spatial alignment of linear molecules along the direction of the light polarization vector. Pendular states are formed. Signatures of such aligned states, some of which also manifest the effects of pendular motion, have been obtained in experiments which measure the angular distributions of fragment ions produced when molecules undergo dissociative ionization due to interaction with linearly polarized laser radiation at a wavelength of 532 nm at intensities of the order 10¹³ W cm ^-2 . Effects of space charge saturation on such angular distributions are explored by conducting experiments at different laser intensities and using two different laser-molecule interaction geometries. Experimental results for the linear triatomic CS₂ , bent triatomics NO₂ and SO₂ , and a tetrahedral polyatomic CCl₄ are compared with model calculations and ab initio molecular structure computations.