https://doi.org/10.1007/s100510170050
Spatial-dispersion and relativistic effects in the optical sum rules
1
International School for Advanced Studies (SISSA) and
Istituto Nazionale per la Fisica della Materia (INFM),
Via Beirut 4, 34014 Trieste, Italy
2
Scuola Normale Superiore,
P.za dei Cavalieri 7, 56126 Pisa, Italy
Corresponding author: a scandolo@princeton.edu
Received:
5
June
2001
Published online: 15 October 2001
We describe a procedure to take into account the spatial dispersion of the optical excitations in the susceptibility sum rules. We show that this implies that relativistic corrections of the same order must be considered. The final result is a decrease of the total oscillator strength equal to the ratio of the average electron kinetic energy with mc2. We propose experiments with synchrotron radiation sources on crystals of heavy elements to observe the described effect.
PACS: 78.20.Ci – Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity) / 78.40.-q – Absorption and reflection spectra: visible and ultraviolet / 71.15.Rf – Relativistic effects
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001
