Berlin 2001 – wissenschaftliches Programm

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AMPD: EPS AMPD

AMPD 2: Sitzung 2

AMPD 2.3: Vortrag

Montag, 2. April 2001, 11:55–12:20, H104

Chirality of highly excited few–electron states — •Jamal Berakdar — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany

Chirality effects, such as optical activity of molecules or circular dichroism in ferromagnets, are intimately related to the presence of a time-odd pseudo vector in the system (e.g., a well–defined angular momentum direction, known spins projection ...). In this report it is shown that a few-electron state which is initially unpolarized attains a chirality upon an excitation by polarized photons or electrons. This effect can be traced back to an interference effect between the real and imaginary (skew-hermitian) parts of the excitation amplitudes. Hence, measurements of these chirality effects reveal information, otherwise unaccessible, on the phase differences between parts of the transition matrix elements. Conditions for the presence and absence of the chirality transfer in the excitation of unpolarized few-electron states by polarized photons and charged particles is illustrated by simple geometric arguments and the conclusions are contrasted with available experiments.