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Multiconfiguration Dirac-Fock method is employed to calculate the excitation energies, ionization potentials, oscillator strengths, and radii for all neutral and up to four times ionized species of element Uuq, as well as the homolog elements Ge, Sn, and Pb. Using an extrapolative scheme, improved ionization potentials of Uuq were obtained with an uncertainty of less than 2000 cm(-1). Two relatively stronger resonance transitions are predicted for the element Uuq. In particular, the strongest line in Uuq, corresponding to the [6d(10)7s(2)7p(3/2)8s(1/2)](1)-->[6d(10)7s(2)7p(3/2)(2)](2) transition at 22 343 cm(-1), just lies in the prime energy region of experimental measurement.

We study few-cycle, strong-field dissociation of aligned H + 2 by solving the time-dependent Schrödinger equation including rotation. We examine the dependence of the final angular distribution, the kinetic energy release spectrum, and the total dissociation yield on the initial nuclear angular distribution. In particular, we look at the dependence on the relative angle θ 0 between the laser polarization and the symmetry axis of a well-aligned initial distribution, as well as the dependence on the delay between the "pump" pulse that prepares the alignment and the few-cycle probe pulse. Surprisingly, we find the dissociation probability for θ 0 = 90• can be appreciable even though the transitions involved are purely parallel. We therefore address the limits of the commonly held "ball-and-stick" picture for molecules in intense fields as well as the validity of the axial recoil approximation.

Theoretical treatments of strong-field physics have long relied on the numerical solution of the time-dependent Schrödinger equation. The most effective such treatments utilize a discrete spatial representation -a grid. Since most strong-field observables relate to the continuum portion of the wave function, the boundaries of the grid -which act as hard walls and thus cause reflection -can substantially impact the observables. Special care thus needs to be taken. While there exist a number of attempts to solve this problem -e.g., complex absorbing potentials and masking functions, exterior complex scaling, and coordinate scaling -none of them are completely satisfactory. The first of these is arguably the most popular, but it consumes a substantial fraction of the computing resources in any given calculation. Worse, this fraction grows with the dimensionality of the problem. And, no systematic way to design such a potential has been used in the strong-field community. In this work, we address these issues and find a much better solution. By comparing with previous widely used absorbing potentials, we find a factor of 3-4 reduction in the absorption range, given the same level of absorption over a specified energy interval.

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