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Dynamics of clusters and molecules in strong electromagnetic fields: A TDDFT-MD approach Ionization Environment Time-resolved dynamics Laser Projectile Fondamental studies of mechanisms of irradiation and response of clusters coupled with environment
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model-potential electrons TDDFT-MD Gen. QM/MM Dyn. polar. TDCI Statics Dynamics ElectronsEnvironment Methods on the market Car-Parinello, BO/MDCar-Parinello, BO QM/MM model-potential electrons Today: CNOH molecules + H 2 O "environment" Na n @Ar,Ne,Kr @ MgO
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Na n n valence e - n ions (Na + ) TDLDA + ADSIC MD-TDDFT(LDA) non-adiab. dynamics (≠BO) explicit pseudopotentials TDDFT-MD laser projectile Today, ions are: C 4+, O 6+, N 7+, H +
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Numerical details represented on 3D grid: 48 3, 64 3, 72 3, 96 3, … Goedecker-like (non-local) dt = 0.5 as 50 fs for H 2 O 64 3 54 h70h 96 2 x 72138 h234 h fixed ionsmoving ions propagation: time-splitting Verlet algorithm box size Home-made codes
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(Time-resolved) observables from electrons: optical response cloud deformation, shape, localization ionization > number of emitted e - > kinetic E spectrum of emitted e - > angular distribution of emitted e - > level depletion from ions: potential and kinetic (temperature) E global deformation and shape bond lengths, energies Today: projectile + H 2 O laser + (H 2 O) H 3 O + laser/proj. + C 2 H 4
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water = electronic insulator gap 10 eV 0.1 au threshold Why TDLDA-MD ? projectile + H 2 O charge velocity 0 adiab. sudden cf. J. Kohanoff
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adiab. Why TDLDA-MD ? charge velocity 0 "fixed e - " + ionic MD sudden e - TDDFT + fixed ions ? ? Which theory for: dynamical description of irradiation and response of electrons and ions ? ? ? H + + H 2 O C + H 2 O
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H + + H 2 O, low v
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C + H 2 O, high v
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Laser irradiation of (H 2 O)H 3 O + E pol I 0 =10 13 W/cm 2 FWHM=20 fs frequency scan IP=-20.6 eV off-resonant but... off-resonant vibrations 2
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C 2 H 4 : optical response IP: -11.7 eV 6.8 eV Yabana, Bertsch (2001) Fourier Transform 8.16 eV136 eV
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Laser pol. I = 10 13 Wcm -2 FWHM = 20 fs C 2 H 4 : laser irradiation below resonanceson resonancewell above resonance
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Ionization (level depletion) from a given electronic level Compare cases with similar (small) net ionization C 2 H 4 : ionization mechanisms
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Ionization Environment Time resolved dynamics Laser Projectile Dynamical description of irradiation and response of electrons and ions with coupling to environment Irradiation of clusters and molecules by intense electro- magnetic fields Environment - Hierarchical model Dynamical QM/MM - Na@Ar, Kr, Ne - Na @ MgO - Na@H 2 O in the oven - C, N, O @ H 2 O in near future - C, N, O @ H 2 O @Ar in future Dynamics of ionization - Self Interaction problem (SIC) - Benchmark TDSIC calculations - Simple approximations in the oven - Dynamical correlations in the future (electronic transport) Time resolved dynamics Key importance of non adiabatic electron-ion dynamics for understanding mechanisms Thanks to E. Suraud, P.-G. Reinhard, Z.P. Wang, U. Ndongmouo, J. Messud S. Vidal, and you for your attention !
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