"Environmented" electronic systems Deposited clusters or molecules: on rare gas surface -> "soft-landing" Fe Ru via Ar [Lau et al., Low Temp. Phys. (2003)] Pt [Levesque et al., Nucl. Instr. Meth. Phys. Res. (2003)] on oxides (MgO,ZnO,Al 2 O 3,…) -> catalysis studies

"Environmented" electronic systems Embedded clusters in rare gas droplets -> control of temperature,size [Bartelt et al., PRL (1996)] free Ag 3 + Ag 3 Ar in rare gas matrices -> "inert" (?) environment [Lecoultre et al., JCP (2007)] [Bonacic-Koutecky et al.,JCP (1999)]

Dynamics ElectronsEnvironment Dynamics of extended systems model-potential (frozen) electrons e - quantal but in ground state electronic excitation All classical charge creation e - quantal but small systems environment Car-Parrinello MD TDDFT-MD TDCI How ?? MM / QM (TDDFT) MM/QM (TDCI) e - excitation charge creation

Standard QM/MM QM: quantum chemistry MM: classical force fields stretching folding twist   electrostatic Van der Waals static parameters Þ static polarization Þ no e - response of MM

D Ar R Ar R ion Generalized QM/MM Na N D O 2- R Mg 2+ Ar, Ne, KrMgO R O 2- frozen cores Madelung potential Lennard-Jones soft Coulomb oscillators Buckingam soft Coulomb oscillators soft Coulomb VdW ab initio + fine-tuning Electrons Generalized MM: explicit dynamical dipoles e - response from MM x no e - emission add new terms in U ext

(Time-resolved) observables from electrons: dipole response (-> spectral analysis) ionization > number of emitted e - > kinetic E spectrum of emitted e - > angular distribution of emitted e - from ions: potential and kinetic (temperature) E global deformation and shape During or after cluster deposition, laser irradiation, … from matrix: potential and kinetic (temperature) E global deformation and shape internal excitation (dipoles)

I III Cluster properties Optical response Photoelectrons II Matrix properties Global excitation Internal excitation Deposition dynamics Energies Site deposition Role of charges Guided tour example of deposition

short–range compressionlong –range polarization Na 8 in Ar 164 Na 6 on MgO(100) final blue-shift x y z subtle balance core repulsion vs. polarization attraction broken x-y degeneracy  geometry Laudau fragmentation  core repulsion oblate Optical response

Exp: Rostock Compression Polarization Caution: "helium blue-shift" embedded clusters Rare gas not that inert… Optical response

Photoelectron angular distributions Na 8 laser pol. I = 10 9 Wcm -2 FWHM = 20 fs  =5.44 eV IP=-4.3 eV no state dependence ! MgO(or Ar) no problem of orientation

Photoelectron angular distributions free orientated Na 8 state PAD,  =2.6 eV Na MgO total PAD, 3  suppression towards surface Na Ar total PAD, 2  No orientation problem but… complex interactions with surface !

I III Cluster properties Optical response Photoelectrons II Matrix properties Global excitation Internal excitation Deposition dynamics Energies Site deposition Role of charges Cluster Electrons Ions Matrix Cores Shells Guided tour example of deposition

Charged atom deposition Na Ar 384 E kin0= 136 meV Na: slight minimum Na + : deep minimum thanks to Ar vacancy fixed layers Inclusion of Na + in a dynamically created Ar vacancy

Deposition of Na dimers Na 2 Ar 384 Na Ar 384 i)Na Ar 384 Na + /Ar 383 more robust attachment when charged

I III Cluster properties Optical response Photoelectrons II Matrix properties Global excitation Internal excitation Deposition dynamics Energies Site deposition Role of charges Cluster Electrons Ions Matrix Cores Shells Guided tour example of deposition

Na 6 deposition, E kin0 = 136 meV/ion fixed Ar coresfixed Ar dipolesfull Ar Dipole d.o.f dynamical dipoles = crucial ingredient for cluster dynamics

at impact… Ar electronic response E kin0 = 136 meV/ionE exc  d 2 Na + Na 6 + Na 6 Na 16 meV9 meV 0.2 meV1.2 meV Na + Na 6 + Na 6 Na c h a r g e e f f e c t > > s i z e e f f e c t

Ar dipoles Q= 0 Na E kin0 = 136 meV Q= 0, +1, -1 Q= +1Q= -1 Important effect of charge Q = 0  high Ar excitation energy Threshold for reflection: factor 20 between Na + and Na Na Q Ar atoms Dipoles ? E kin0 = 6.8 eV Time evolution of dipoles

Na E kin0 = 800 meV/ion Impact Longer time Radial dipole distribution at different times Localized excitation Sizeable dipole "noise" Moderate time evolution Dipole localization Initial

Conclusion and perspectives Clusters and environment o Hierarchical approach for a generalized QM/MM Na done Na done dynamical electronic response of substrate Na with defects in progress o H 2 O in near future o H 2 rare gas in future M. Farizon L. Sanche

Clustersdeposited on surface embedded in matrix free Exp Theory (nano)technologies surface engineering Particular interest: rare gas substrates (Ne, Ar, Kr) « soft-landing » Ag Pt(111) via Ar Bromann et al., Science 274, (1996) 956 Fe Ru(001) via Ar Lau et al., Low Temp. Phys. 29 (2003) 296 Context and motivations

Harbich et al., PRB 76 (2007) Ag N + codeposited with fluorescence Ag luminescence Ag 1 + Neutralization ofAg N + by i.e - from Au then ii.going through Ar  non trivial electronic effect of Ar matrix Context and motivations

Na 6 deposited on MgO structure mismatch energy dependence site dependence

P.M.Dinh, Séminaire LCPQ/LPT, 19 juin 2008 initial Seifert et al., Appl. Phys. B 71 (2000) 795 Réponse optique Na 434 Na h  = 1.9 eV I = 2×10 12 W.cm -2 Δt = 50 fs (FWHM) élargissement vers le rouge en accord avec exp