<div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr"><br>SEMINARIO CONJUNTO EN EL DEPARTAMENTO DE FÍSICA EXACTAS - UBA<br><br><br> En el Aula Seminario, 2do piso, Pab. I,<br><br> Lunes 18/12, 14hs:</div><div dir="ltr"><br><br><div>1. <span style="font-size:12.8px"><b>Correlated electron-nuclear dynamics</b></span> </div><div><div style="font-size:12.8px"> ALI ABEDI<br></div><div><span style="font-size:12.8px"> Universidad del Pais Vasco</span><br></div><div style="font-size:12.8px"> </div><span style="font-size:12.8px">2. <b>The exact potential driving the electron dynamics in enhanced ionization of H2+- isotopes effects</b></span><br style="font-size:12.8px"></div><div><span style="font-size:12.8px"> ELHAM KHOSRAVI</span><span style="font-size:12.8px"><b><br></b></span></div><div><span style="font-size:12.8px"> Universidad del Pais Vasco</span><span style="font-size:12.8px"><b><br></b></span></div><div><span style="font-size:12.8px"><br></span></div> <br><br><b>Correlated Electron-Nuclear Dynamics</b><br><br>The coupling between electronic and nuclear motion plays an important role in many fascinating phenomena, such as superconductivity, the process of vision, as well as photo-synthesis. There are standard approximations such as Ehrenfest dynamics or surface hopping that partially capture the non-adiabatic effects. As a first step towards a full ab-initio treatment of the coupled electron-nuclear system, we deduce an exact factorization of the complete wavefunction into a purely nuclear part and a many-electron wavefunction which parametrically depends on the nuclear configuration. We derive formally exact equations of motion for the nuclear and electronic wavefunctions [1-3]. These exact equations lead to a rigorous definition of time-dependent potential energy surfaces (TDPES) as well as time-dependent geometric phases. We analyze features of the TDPES in two topically demanding situations: <br>molecules in strong fields [1-3] and splitting of a nuclear wave-packet at avoided crossings [5] Born-Oppenheimer potential energy surfaces. In addition, by studying a numerically exactly solvable model we demonstrate that the molecular Berry phase and the corresponding non-analyticity in the electronic Born-Oppenheimer wavefunction is, in general, not a true topological feature of the exact solution of the full electron-nuclear Schroedinger equation and only appear in the limit of infinite nuclear mass [4].<br><br>Finally, we present a novel mixed quantum-classical approach [5] to the coupled electron-nuclear dynamics based on the equations of motion for the electronic and nuclear subsystems within the exact factorization framework. The nuclear equation is a standard Schroedinger equation containing a TDPES as well as a time-dependent vector potential. Starting from these equations, the correct classical limit of the nuclear dynamics is worked out by taking the classical limit of the exact time-dependent Schroedinger equation satisfied by the nuclear wave function. The effect of the time-dependent scalar and vector potentials, representing the exact electronic back-reaction on the nuclear subsystem, is consistently derived within the classical approximation. Using a model system, we examine the performance of the proposed mixed quantum-classical scheme in comparison with exact calculations, in the presence of strong non-adiabatic coupling between the electronic and nuclear motion.<br><br>References:<br>[1] A. Abedi, N. T. Maitra, and E. K. U. Gross, Physical Review Letters 105 123002 (2010). <br>[2] A. Abedi, N. T. Maitra, and E. K. U. Gross, Journal of Chemical Physics 137 22A530 (2012)<br>[3] A. Abedi, F. Agostini, Y. Suzuki, E. K. U. Gross, Physical Review Letters 110 263001 (2013).<br>[4] S. K. Min, A. Abedi, K. S. Kim, and E. K. U. Gross, Physical Review Letters 113 263004 (2014).<br>[5] A. Abedi, F. Agostini, and E. K. U. Gross, Europhysics Letters 106 33001 (2014).<br><br><div><br></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px"><br></span></div><div><b style="font-size:12.8px">The exact potential driving the electron dynamics in enhanced ionization of H2+- isotopes effects</b><span style="font-size:12.8px"><br></span></div><div><b style="font-size:12.8px"><br></b></div><div><div><span style="font-size:12.8px">The exact potential [1] driving the electron's dynamics [2] in enhanced</span></div><div><span style="font-size:12.8px">ionization of H2+ can have large contributions arising from dynamical electron-</span></div><div><span style="font-size:12.8px">nuclear correlation, going beyond what any Coulombic-based model can</span></div><div><span style="font-size:12.8px">provide [3]. This potential is defined via the exact factorization of the molecular</span></div><div><span style="font-size:12.8px">wavefunction that allows the construction of a Schrödinger equation for the</span></div><div><span style="font-size:12.8px">electronic system, in which the potential contains exactly the effect of coupling</span></div><div><span style="font-size:12.8px">to the nuclear system and any external fields [1,2]. To investigate nuclear-mass-</span></div><div><span style="font-size:12.8px">dependence in enhanced ionization, we study isotopologues of H2+ . We</span></div><div><span style="font-size:12.8px">decompose the exact potential into components that naturally arise from the</span></div><div><span style="font-size:12.8px">conditional wavefunction, and also into components arising from the marginal</span></div><div><span style="font-size:12.8px">electronic wavefunction, and compare the performance of propagation on these</span></div><div><span style="font-size:12.8px">different components as well as approximate potentials based on the quasi-</span></div><div><span style="font-size:12.8px">static or Hartree approximation with the exact propagation [4].</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">References:</span></div><div><span style="font-size:12.8px">[1]. A. Abedi, N. T. Maitra, and E. K. U. Gross, Phys. Rev. Lett. 105, 123002 </span><span style="font-size:12.8px">(2010).</span></div><div><span style="font-size:12.8px">[2]. Y. Suzuki, A. Abedi, N. T. Maitra, K. Yamashita, and E. K. U. Gross, </span><span style="font-size:12.8px">Phys. Rev. A 89, 040501 (2014).</span></div><div><span style="font-size:12.8px">[3]. E. Khosravi, A. Abedi, and N. T. Maitra, Phys. Rev. Lett. 115, 263002 </span><span style="font-size:12.8px">(2015)</span></div><div><span style="font-size:12.8px">[4]. E. Khosravi, A. Abedi, A. Rubio, N. T. Maitra, PCCP, 19 , 8269 (2017)</span></div></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px"><br></span></div></div></div></div>
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