title: Quantum wave-packet dynamics in spin-coupled vibronic states.
abstract: Extending the Shin-Metiu two-electron Hamiltonian, we construct a new Hamiltonian with effective singlet-triplet couplings. The Born-Oppenheimer electronic potentials and couplings are obtained for different parameters, and the laser-free dynamics is calculated with the full Hamiltonian and in the adiabatic limit. We compare the dynamics of the system using nuclear wave packets for different numbers of Born-Oppenheimer potentials and vibronic wave packets on a full 3-dimensional (two electron coordinates plus one nuclear coordinate) grid. Using strong fields, we show that it is possible to dynamically lock the spin state of the system by decoupling the singlet-triplet transition via a nonresonant dynamic Stark effect in the adiabatic limit. Although a similar spin-locking mechanism is observed in the dynamics of vibronic wave packets, multiphoton ionization cannot be neglected leading to the breakdown of the control scheme.
authors.affiliation: Institut für Physikalische und Theoretische Chemie and Röntgen Research Center for Complex Material Systems Campus Nord, Universität Würzburg, Emil-Fischer-Straße 42, 97074 Würzburg, Germany.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Falge
authors.forename: Volker
authors.initials: V
authors.lastname: Engel
authors.forename: Manfred
authors.initials: M
authors.lastname: Lein
authors.forename: Patricia
authors.initials: P
authors.lastname: Vindel-Zandbergen
authors.forename: Bo Y
authors.initials: BY
authors.lastname: Chang
authors.forename: Ignacio R
authors.initials: IR
authors.lastname: Sola
mesh_terms: D011789:Quantum Theory; D014732:Vibration