Disentangling molecular alignment and enhanced ionization in intense laser fields

Using circular and linear laser polarization for strong-held dissociative ionization we show that iodine molecules are rotationally fixed by their own moment of inertia during the dissociative ionization with a 80-fs pulse. What seems to be alignment of the fragments is created by an enhancement of the ionization rate, which is strongly dependent on the angle between the molecular axis and the laser electric-field vector. By the introduced method we can measure the degree of alignment for I-2 Br-2, Cl-2, and O-2 and independently estimate the enhancement of the ionization rate for I-2. [S1050-2917(99)50105-4]. PACS number(s): 33.80.Rv, 33.90.+h, 31.50.Vk.