Giant resonances of endohedral atoms
M. Ya. Amusia+*, A. S. Baltenkov∇, L. V. Chernysheva*
+Racah Institute of Physics, the Hebrew University, 91904 Jerusalem, Israel
*Ioffe Physical-Technical Institute, 194021 St.-Petersburg, Russia
∇Arifov Institute of Electronics, 100125 Tashkent, Uzbekistan
PACS: 31.25.-v, 32.80.-t
Abstract
We demonstrate for the first time that the effect of fullerene
shell upon photoionization of the "caged" atom in an endohedral can result
in formation of Giant Endohedral Resonances or GER. This is illustrated by
the concrete case of Xe@C60 photoionization cross-section that exhibits
at 17 eV a powerful resonance with total oscillator strengths of about 25.
The prominent modification of the 5p6 electron photoionization
cross-section of Xe@C60 takes place due to strong fullerene shell
polarization under the action of the incoming electromagnetic wave and
oscillation of this cross-section due to the reflection of the photoelectron
from Xe by the C60. These two factors transform the smoothly decreasing
5p6 cross-section of Xe into a rather complex curve with a powerful maximum
for Xe@C60, with the oscillator strength of it being equal to 25! We
present also the results for the dipole angular anisotropy parameter that is
strongly affected by the reflection of the photoelectron waves but not
modified by C60 polarization.