Muonic molecular ions pp mu and pd mu, driven by superintense VUV laser pulses
- The non-Born-Oppenheimer quantum dynamics of pp mu and pd mu molecular ions excited by ultrashort, superintense VUV laser pulses polarized along the molecular axis (z) is studied by the numerical solution of the time-dependent Schrodinger equation within a three-dimensional (3D) model, including the internuclear distance R and muon coordinates z and rho, a transversal degree of freedom. It is shown that in both pp mu and pd mu, muons approximately follow the applied laser field out of phase. After the end of the laser pulse, expectation values < z >, < p >, and < R > demonstrate "post-laser-pulse" oscillations in both pp mu and pd mu. In the case of pd mu, the post-laser-pulse oscillations of < z > and < R > appear as shaped "echo pulses." Power spectra, which are related to high-order harmonic generation (HHG), generated due to muonic and nuclear motion are calculated in the acceleration form. For pd mu it is found that there exists a unique characteristic frequency omega(pd mu)(osc) representing both frequencies of post-laser-pulseThe non-Born-Oppenheimer quantum dynamics of pp mu and pd mu molecular ions excited by ultrashort, superintense VUV laser pulses polarized along the molecular axis (z) is studied by the numerical solution of the time-dependent Schrodinger equation within a three-dimensional (3D) model, including the internuclear distance R and muon coordinates z and rho, a transversal degree of freedom. It is shown that in both pp mu and pd mu, muons approximately follow the applied laser field out of phase. After the end of the laser pulse, expectation values < z >, < p >, and < R > demonstrate "post-laser-pulse" oscillations in both pp mu and pd mu. In the case of pd mu, the post-laser-pulse oscillations of < z > and < R > appear as shaped "echo pulses." Power spectra, which are related to high-order harmonic generation (HHG), generated due to muonic and nuclear motion are calculated in the acceleration form. For pd mu it is found that there exists a unique characteristic frequency omega(pd mu)(osc) representing both frequencies of post-laser-pulse muonic oscillations and the frequency of nuclear vibrations, which manifest themselves by very sharp maxima in the corresponding power spectra of pd mu. The homonuclear pp p. ion does not possess such a unique characteristic frequency. The "exact" dynamics and power, and HHG spectra of the 3D model are compared with a Born-Oppenheimer, fixed-nuclei model featuring interesting differences: postpulse oscillations are absent and HHG spectra are affected indirectly or directly by nuclear motion.…
