Spatial effects in the intense field ionization of N-2 molecules by femtosecond-duration laser pulses

Spatially resolved time-of-flight measurements have been made of laser-indu ced multiple ionization of N-2 molecules in intensity-selective fashion usi ng 100 fs long light pulses of 806 nm wavelength, over an intensity range 1 0(13)-10(15) W cm(-2). The spatial dependence of the laser intensity within the laser-molecule interaction zone determines the overall ionization dyna mics. Different processes are shown to dominate in different intensity (spa tial) regimes, leading to an inhomogeneous distribution of N-2(+) and N-4() (q greater than or equal to 1) ions and their kinetic energies in the las er focal volume. Implications are discussed for experiments that aim to pro be phenomena such as bond softening and above-threshold dissociation.