https://doi.org/10.1007/s100510050418
Fano-like coupling of collective and particle-hole excitations in Li metal
Institute of Physics, University of Dortmund,
44221 Dortmund, Germany
Corresponding author: a schuelke@physik.uni.dortmund.de
Received:
29
December
1998
Accepted:
16
March
1998
Published online: 15 September 1998
The dynamic structure factor
of Li with
[110] and 0.88 a.u.
< q< 1.03 a.u.,
as measured with 1 eV resolution by means of synchrotron
radiation based inelastic
X-ray scattering spectroscopy (IXSS), exhibits, in the
energy loss range between 3
and 12 eV, a fine structure, which
appears as a resonance around 4 eV and an
antiresonance around 8 eV,
when the difference between the experimental
-spectra with
[110]
and
[111]
is considered. In order to find out the origin of
this fine structure we have interpreted
recent TLDA (time dependent local density
approximation) calculations of the
Li- [CITE],
which were based on the inversion of the full dielectric matrix, by
utilizing a simple two-plasmon-band model. In this
way the fine structure can be
traced back to a Fano-like coupling of the
discrete collective excitations (both the
regular plasmon and the so-called
zone-boundary collective states (ZBCS's)) and
the particle-hole excitation continuum, mediated by the
off-diagonal elements of
the dielectric matrix,
, where
(1,1,0).
PACS: 71.45.Gm – Exchange, correlation, dielectric and magnetic functions, plasmons / 78.70.Ck – X-ray scattering / 71.20.Dg – Alkali and alkaline earth metals
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1998
