Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 1: Posters Monday (Cluster, Atoms in Fields)

A 1.29: Poster

Montag, 2. April 2001, 12:30–15:00, AT3

Dynamics of angular momentum coupling in an arbitrarily oriented magnetic field: classical results form a rigorous quantum mechanical calculation — •Michael Brieger — DLR, Institute of Technical Physics, Pfaffenwaldring 38-40, D-70569 Stuttgart, Germany

With an unpaired s electron and a nuclear spin I = 1/2 , the electronic ground states in H and Ag have four hfs sublevels |F,M_F> that are mixed in an arbitrarily oriented magnetic field by giving rise to a four-dimensional system of coupled linear differential equations of first order for the amplitudes when an expansion of the wave function into a time-dependent superposition of the relevant uncoupled basis vectors is inserted into the time-dependent Schrödinger equation. The rigorous analytical solutions obtain the energy eigenvalues and the components of the basis vectors that form the eigenfunctions in the field. If the eigenfunctions are kept as superpositions of their basis vectors, the most general wave function generates expectation values for the Cartesian components of the total magnetic moment that behave fully classically: apart from forcing the total magnetic moment into an overall Larmor precession about the direction of the field, the different pulls on the electronic and nuclear magnetic moments alter the dynamics of angular momentum coupling in the field. This results in an additional stationary magnetization and an oscillation of the coupling angle. The latter effects a periodic exchange of energy between the hfs interaction and the interaction with the external field and, so, makes the expectation value of the total energy a time average and constant.