Starting from a system of electrons and nuclei and their equations of motion, a short deBroglie wavelength approximation for nuclear motions leads to selfconsistent couplings of nuclear trajectories and electronic rearrangements. This presentation emphasizes the importance of choosing the necessary initial conditions in the phase space of nuclear variables to describe a many-atom system by means of bundles of trajectories. It proceeds from wavefunctions to density matrices to allow for explicit treatment of electrons in ab initio descriptions of electronic states, and to incorporate thermal distributions. Numerical propagation methods have been developed to calculate density matrices rapidly changing over time while driven by slow trajectories. The treatments are illustrated with applications to photodissociation of diatomics, photodesorption of molecules, electronic transitions in atomic collisions and in atomic clusters, and electronic photoexcitation at nanostructured surfaces (D. A. Micha, Mol. Phys. 108, 2877 (2010); K. Runge and D. A. Micha, Mol. Phys. 108, 3213 (2010)). Ongoing related research deals with dissipative molecular dynamics, and with a quantum-hydrodynamical treatment (D. Bousquet, K. H. Hugues, D. A. Micha, and I. Burghardt, J. Chem. Phys. 134, 064116 (2011)). * Work partly supported by the Chemistry Division of the National Science Foundation of the USA, and by the Dreyfus Foundation.** Work done in collaboration with I. Burghardt, A. S. Leathers, A. Pacheco, A. Reyes, K.Runge, A. Salam, A. Santana, and B. Thorndyke.

First principles quantum-classical dynamics: From few atoms to condensed matter with a density matrix treatment

243rd National Meeting (2012)

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