Laser-assisted two-color two-photon double ionization of helium atoms

Correlated momentum and kinetic energy distributions of two photoelectrons in laser-assisted two-color two-photon double ionization of helium are investigated by numerically solving a one-plus-one dimensional time-dependent Schr\"{o}dinger equation (TDSE). We find that the weak assisting laser field can act as an energy transferring field, resulting in burst of double ionization. More importantly, the participation of the laser photon into the double ionization reshapes the correlation patterns in the momentum and kinetic energy distributions. The laser photon can be absorbed by any one of the two electrons, providing two channels that induces destructive interference in the correlated momentum and kinetic energy distributions, which is never found in previous work.

The H2+ + HD reaction at low collision energies: H3+/H2D+ branching ratio and product-kinetic-energy distributions

The reactions between H2+ and HD forming H3+ + D as well as H2D+ + H were measured at collision energies between 0 and kB·30 K and a resolution of 75 mK and the H3+/H2D+ product branching ratio and the product kinetic-energy distribution were determined.

Correlated transitions in symmetric and dominant fission modes, and multipole moments of fission fragments

Systematic and anomalous trends in fragment mass and TKE (total kinetic energy) distributions are investigated in terms of 4D Langevin model developed at Tokyo Tech. We have found that correlated transitions in symmetric components and dominant modes (symmetric v.s. asymmetric) can explain the prominent systematic and anomalous features of fission observables. We have also elucidated that interplay between spherical and deformed magicity at A=132 and A=142 to 144 is important in both observables.

Fission modes in fermium isotopes with Brownian shape-motion model

Fission-fragment mass and total-kinetic-energy distributions following fission of the fermium isotopes 256,258,260Fm at low excitation energy have been calculated using the Brownian shape-motion model. A transition from asymmetric fission in 256Fm to symmetric fission in 258Fm is obtained. The total-kinetic-energy distributions for the three isotopes show radically different behaviour due to varying contributions from different fission modes, with a double-humped distribution for 258Fm.

Fission fragment mass and total kinetic energy distributions of spontaneously fissioning plutonium isotopes

The fission-fragment mass and total kinetic energy (TKE) distributions are evaluated in a quantum mechanical framework using elongation, mass asymmetry, neck degree of freedom as the relevant collective parameters in the Fourier shape parametrization recently developed by us. The potential energy surfaces (PES) are calculated within the macroscopic-microscopic model based on the Lublin-Strasbourg Drop (LSD), the Yukawa-folded (YF) single-particle potential and a monopole pairing force. The PES are presented and analysed in detail for even-even Plutonium isotopes with A = 236–246. They reveal deep asymmetric valleys. The fission-fragment mass and TKE distributions are obtained from the ground state of a collective Hamiltonian computed within the Born-Oppenheimer approximation, in the WKB approach by introducing a neck-dependent fission probability. The calculated mass and total kinetic energy distributions are found in good agreement with the data.