An extension of the nonadiabatic quantum molecular dynamics approach is presented to account for electron-nuclear correlations in the dynamics of atomic many-body systems. The method combines electron dynamics described within time-dependent density-functional or Hartree-Fock theory with trajectory-surface-hopping dynamics for the nuclei, allowing us to take into account explicitly a possible external laser field. As a case study, a model system of H++H collisions is considered where full quantum-mechanical calculations are available for comparison. For this benchmark system the extended surface-hopping scheme exactly reproduces the full quantum results. Future applications are briefly outlined.

An extension of the nonadiabatic quantum molecular dynamics approach is presented to account for electron-nuclear correlations in the dynamics of atomic many-body systems. The method combines electron dynamics described within time-dependent density-functional or Hartree-Fock theory with trajectory-surface-hopping dynamics for the nuclei, allowing us to take into account explicitly a possible external laser field. As a case study, a model system of H++H collisions is considered where full quantum-mechanical calculations are available for comparison. For this benchmark system the extended surface-hopping scheme exactly reproduces the full quantum results. Future applications are briefly outlined.

An extension of the nonadiabatic quantum molecular dynamics approach is presented to account for electron-nuclear correlations in the dynamics of atomic many-body systems. The method combines electron dynamics described within time-dependent density-functional or Hartree-Fock theory with trajectory-surface-hopping dynamics for the nuclei, allowing us to take into account explicitly a possible external laser field. As a case study, a model system of H++H collisions is considered where full quantum-mechanical calculations are available for comparison. For this benchmark system the extended surface-hopping scheme exactly reproduces the full quantum results. Future applications are briefly outlined.

Photoinduced excitation and relaxation of organic molecules (C2H4 and CH2NH+2) are investigated by means of nonadiabatic quantum molecular dynamics with hopping (NA-QMD-H), developed recently [Fischer, Handt, and Schmidt, paper I of this series, Phys. Rev. A 90, 012525 (2014)]. This method is first applied to molecules assumed to be initially ad hoc excited to an electronic surface. Special attention is drawn to elaborate the role of electron-nuclear correlations, i.e., of quantum effects in the nuclear dynamics. It is found that they are essential for a realistic description of the long-time behavior of the electronic relaxation process, but only of minor importance to portray the short-time scenario of the nuclear dynamics. Migration of a hydrogen atom, however, is identified as a quantum effect in the nuclear motion. Results obtained with explicit inclusion of an fs-laser field are presented as well. It is shown that the laser-induced excitation process generally leads to qualitatively different gross features of the relaxation dynamics, as compared to the field-free case. Nevertheless, the nuclear wave packet contains all subtleties of the cis-trans isomerization mechanism as observed without a laser field.

An extension of the nonadiabatic quantum molecular dynamics approach is presented to account for electron-nuclear correlations in the dynamics of atomic many-body systems. The method combines electron dynamics described within time-dependent density-functional or Hartree-Fock theory with trajectory-surface-hopping dynamics for the nuclei, allowing us to take into account explicitly a possible external laser field. As a case study, a model system of H++H collisions is considered where full quantum-mechanical calculations are available for comparison. For this benchmark system the extended surface-hopping scheme exactly reproduces the full quantum results. Future applications are briefly outlined.

Photoinduced excitation and relaxation of organic molecules (C2H4 and CH2NH+2) are investigated by means of nonadiabatic quantum molecular dynamics with hopping (NA-QMD-H), developed recently [Fischer, Handt, and Schmidt, paper I of this series, Phys. Rev. A 90, 012525 (2014)]. This method is first applied to molecules assumed to be initially ad hoc excited to an electronic surface. Special attention is drawn to elaborate the role of electron-nuclear correlations, i.e., of quantum effects in the nuclear dynamics. It is found that they are essential for a realistic description of the long-time behavior of the electronic relaxation process, but only of minor importance to portray the short-time scenario of the nuclear dynamics. Migration of a hydrogen atom, however, is identified as a quantum effect in the nuclear motion. Results obtained with explicit inclusion of an fs-laser field are presented as well. It is shown that the laser-induced excitation process generally leads to qualitatively different gross features of the relaxation dynamics, as compared to the field-free case. Nevertheless, the nuclear wave packet contains all subtleties of the cis-trans isomerization mechanism as observed without a laser field.