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Algebraic collective model (ACM) calculations for the even-even selenium isotopes $^{86,88}\mathrm{Se}$ have been performed to describe collective properties of these two transitional nuclei with only two and four valence neutrons, respectively. From the perspective of the ACM the nuclei turn out to be only weakly deformed, described by a very $\ensuremath{\gamma}$-soft potential. This is confirmed by Skyrme and Gogny energy density functional calculations. Additionally, the fully microscopic symmetry conserving configuration mixing method with the Gogny interaction has been applied to the study of these isotopes. The results show the transitional character of $^{86}\mathrm{Se}$ and the relevant role of the triaxial degree of freedom in the structure of these nuclei.

We investigate from a theoretical perspective a possible pump and probe scenario for analyzing the rotational motion of free deformed metal clusters considering as test case an ensemble of Na7+ clusters. To that end, we develop a simple classical model for the orientational dynamics and rate equations for the ionizing effect of laser pulses. The model parameters are determined microscopically by time-dependent density functional theory for the cluster electrons and a detailed description of the cluster ions by local pseudo-potentials. We find that pump and probe analysis can very well resolve the rotational motion provided that the laser parameters are properly tuned to the Me surface plasmon of the given sample. Moreover, we see that the laser pulses burn a hole into the distribution of orientations. Stroboscopic repetition of pulses will allow to produce an ensemble clusters oriented in a direction perpendicular to the laser polarization axis.

We discuss the response of the H9+ cluster to an excitation by an intense laser beam. Calculations are done within the framework of TDLDA-MD, an approach which has proven to provide a robust tool for investigations in metal cluster dynamics. We first discuss static and low energy properties of H9+ and make comparisons with other existing ab initio results. We then explore the various excitation/deexcitation scenarios as a function of the laser parameters.

We compare the capabilities of rapid highly charged projectiles and intense femtosecond lasers to ionize simple metal clusters while leaving as little intrinsic excitation as possible in the residue. We show that both excitation mechanisms are able to produce highly charged clusters. The deposited excitation energies increase with ionization but with different trends. Cold ionization, corresponding to moderate deposited excitation energy, is better attained with ionic projectiles for low charge states, and with lasers for high charge states.

International audience; Photoinduced molecular processes start with the interaction of the instantaneous electric field of the incident light with the electronic degrees of freedom. This early attosecond electronic motion impacts the fate of the photoinduced reactions. We report the first observation of attosecond time scale electron dynamics in a series of small- and medium-sized neutral molecules (N2, CO2, and C2H4), monitoring time-dependent variations of the parent molecular ion yield in the ionization by an attosecond pulse, and thereby probing the time-dependent dipole induced by a moderately strong near-infrared laser field. This approach can be generalized to other molecular species and may be regarded as a first example of molecular attosecond Stark spectroscopy.

The width of the plasmon resonance in the clusters ${\mathrm{Na}}_{9}^{+}$, ${\mathrm{Na}}_{21}^{+}$, and ${\mathrm{Na}}_{41}^{+}$ is investigated in the framework of the structure-averaged jellium model and compared with recent experimental data. The two leading mechanisms for the line broadening are fragmentation of the resonance into nearby 1ph states and splitting through thermal quadrupole fluctuations. The fragmentation becomes activated mainly through octupole fluctuations and it gives the dominating contribution to the width.

The density‐constrained time‐dependent Hartree‐Fock (DC‐TDHF) theory is a fully microscopic approach for calculating heavy‐ion interaction potentials and fusion cross sections below and above the fusion barrier. We discuss applications of DC‐TDHF method to fusion, the effects of neutron transfer, and potential application to fission barrier calculations.

We discuss the response of metal clusters subject strong electromagnetic fields in the framework of density functional theory. This allows a fully nonadiabatic treatment of both electronic and ionic degrees of freedom. We give a few general properties of metal clusters which can be accessed with this kind of nonadiabatic approaches and we present an example of application of a metal cluster subject to an intense laser field.

Inelastic contributions to photon scattering off nuclei in the Δ-resonance region are calculated assuming a Δ-dominated elementary photon-nucleon scattering amplitude and neglecting Δ-propagation. The inelastic scattering amplitude can then be expressed in terms of transition form factors. Evaluating these in a simple 1p-1h model for the excited states for 12 C and 208 Pb we find sizeable inelastic contributions to higher spin states, which exceed the elastic cross section by an order of magnitude at higher momentum transfer. The actual size of inelastic contributions depends sensitively on the range of excitation energies taken into account.