  We investigate the core level spectra of Ca(1-x)Sr(x)RuO(3) employing high
resolution photoemission spectroscopy. Sample surface appears to be dominated
by the contributions from Ru-O layers. Sr 3p core level spectra are sharp and
asymmetric in SrRuO(3) as expected in a metallic system, and exhibit multiple
features for the intermediate compositions that can be attributed to the
difference in Ca-O and Sr-O covalency. The Ru core level spectra exhibit
distinct signature of satellite features due to the finite electron
correlations strength among Ru 4d electrons. The intensity of the satellite
feature is weaker in the surface spectra compared to the bulk. The low
temperature spectra exhibit enhancement of satellite intensity in the spectra
corresponding to ferromagnetic compositions due to the inter-site exchange
coupling induced depletion of the intensity at the Fermi level. The increase in
x leads to a decrease in satellite intensity that has been attributed to the
increase in hopping interaction strength due to the enhancement of the Ru-O-Ru
bond angle. Evidently, the complex electronic properties of these materials are
derived from the interplay between the electron correlation and hopping
interaction strengths.
