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Hierarchical method for the dynamics of clusters and molecules in contact with an environment

Contacts with insulators (ionic crystals, rare gases…) Structure and low energy dynamics Irradiation dynamics. Hierarchical method for the dynamics of clusters and molecules in contact with an environment. Molecules/clusters + environment (embedded/deposited)

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Hierarchical method for the dynamics of clusters and molecules in contact with an environment

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  1. Contacts with insulators (ionic crystals, rare gases…) Structure and low energy dynamics Irradiation dynamics Hierarchical method for the dynamics of clusters and molecules in contact with an environment Molecules/clusters + environment (embedded/deposited) Fundamental studies on mechanisms (Nano)Technological applications (size controlled deposition…) M. Baer, P. G. Reinhard (Erlangen), M. Dinh, ES (Toulouse)

  2. Density Functional Theory (DFT) Ensemble of orbitals (1 electron) / no correlation One body density Effective mean field theory (Kohn-Sham) Kohn-Sham potential Ions + ext. Local Density Approximation (LDA) Hartree Exch. + Corr. Self Interaction Correction (SIC) Time Dependent (TD)LDA  TDSIC !? Model for free clusters  Electrons Ions Explicit ions via pseudo potentials Detail of structure + ionic Molecular Dynamics (MD)

  3. Ions Na, K (Cs, Ag…) RI Positions Dipoles Metal cluster in an environment Hierarchical approach: Model for free clusters + Polarizable matrix + Couplings Electrons fi Equations of motion by variation of total energy TDLDA for electrons MD for ions MD for atoms (positions AND dipoles) Atoms Ar, Ne, Kr, MgO…

  4. Na6 @MgO free Delicate balance Short range compression (blue) Long range polarization (red) Optical response

  5. Polarization Caution: « Helium blue shift » Exp: Rostock More detailed investigations … Compression Optical response (cont’d)

  6. Distribution of dipole energy at time of impact x [a0] Key role of environment’s degrees of freedom Subtle energy exchanges Charge Response of environment Na6@Ar(100) Ekin = 800 meV Na – Na ~ 800 meV Ar – Ar ~ 50 meV Na -Ar ~ 5 meV

  7. Some conclusions and perspectives ▶Low energy response of cluster’s in contact with an environment Hierarchical model Microscopic electrons, classical polarization… (QM/MM) Delicate interplay of competing effects Subtle energy balance Key role of environment’s degrees of freedom ▶Some open questions  Towards irradiation dynamics Clusters and « bio » molecules under irradiation (laser, ions…)  Formal difficulties SIC and beyond…, TDSIC…

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