  We used six simultaneous XMM-Newton and Rossi X-ray Timing Explorer plus five
Suzaku observations to study the continuum spectrum and the iron emission line
in the neutron-star low-mass X-ray binary 4U 1636-53. We modelled the spectra
with two thermal components (representing the accretion disc and boundary
layer), a Comptonised component (representing a hot corona), and either a
Gaussian or a relativistic line component to model an iron emission line at
about 6.5 keV. For the relativistic line component we used either the diskline,
laor or kyrline model, the latter for three different values of the spin
parameter. The fitting results for the continuum are consistent with the
standard truncated disc scenario. We also find that the flux and equivalent
width of the iron line first increase and then decrease as the flux of the
Comptonised component increases. This could be explained either by changes in
the ionisation state of the accretion disc where the line is produced by
reflection, or by light bending of the emission from the Comptonised component
if the height at which this component is produced changes with mass accretion
rate.
