Ground-state energy and relativistic corrections for positronium hydride

Variational calculations of the ground state of positronium hydride (HPs) are reported, including various expectation values, electron-positron annihilation rates, and leading relativistic corrections to the total and dissociation energies. The calculations have been performed using a basis set of 4000 thoroughly optimized explicitly correlated Gaussian basis functions. The relative accuracy of the variational energy upper bound is estimated to be of the order of 2×10−10, which is a significant improvement over previous nonrelativistic result

Strong laser-pulse-driven ionization and Coulomb explosion of hydrocarbon molecules

Field ionization and Coulomb explosion of small hydrocarbon molecules driven by intense laser pulses are studied in a combined theoretical and experimental framework. The spectra of ejected protons calculated by the time-dependent density functional approach are in good agreement with the experimental data. The results of the simulations give detailed insight into the correlated electron and nuclear dynamics and complement the experiment with a time-dependent physical picture. It is demonstrated that the Coulomb explosion in the studied molecular systems is a sudden, all-at-once fragmentation where the ionization step is followed by a simultaneous ejection of the charged fragment

Strong laser-pulse-driven ionization and Coulomb explosion of hydrocarbon molecules

Field ionization and Coulomb explosion of small hydrocarbon molecules driven by intense laser pulses are studied in a combined theoretical and experimental framework. The spectra of ejected protons calculated by the time-dependent density functional approach are in good agreement with the experimental data. The results of the simulations give detailed insight into the correlated electron and nuclear dynamics and complement the experiment with a time-dependent physical picture. It is demonstrated that the Coulomb explosion in the studied molecular systems is a sudden, all-at-once fragmentation where the ionization step is followed by a simultaneous ejection of the charged fragment

Elastic positronium-atom scattering using the stochastic variational method

The stochastic variational method is used in conjunction with stabilization ideas to compute the low energy phase shifts and scattering lengths for positronium-atom scattering. Results are obtained for the Ps-H, Ps-Li+, Ps-He, and Ps-Ps systems. The Ps-H scattering lengths are probably accurate to better than 5% and are the most accurate so far computed. The results for Ps-Li+ and Ps-Ps scattering represent the first published scattering lengths for these systems. The positive scattering length for completely spin-aligned (3)Ps-(3)Ps scattering, namely 2.95a(o), is particularly significant since it demonstrates the feasibility of forming a stable Bose-Einstein condensate of (3)Ps atoms

Laser-induced electron emission from nanostructures: A first-principles study

Time-dependent density functional theory simulation of laser-induced ionization is presented. Various test systems including a small wire-like molecule, C12H14, as well as carbon nanotubes with varying diameter are studied. It has been demonstrated that significant ionization electron current is produced when a laser pulse is applied. Moreover, pulse-like patterns of the current have been observed, which suggests that short laser pulses can be used to create spatially and temporally localized electron source

Laser-induced electron emission from nanostructures: A first-principles study

Time-dependent density functional theory simulation of laser-induced ionization is presented. Various test systems including a small wire-like molecule, C12H14, as well as carbon nanotubes with varying diameter are studied. It has been demonstrated that significant ionization electron current is produced when a laser pulse is applied. Moreover, pulse-like patterns of the current have been observed, which suggests that short laser pulses can be used to create spatially and temporally localized electron source