  The inelastic x-ray scattering spectrum for phonons of $\Delta_{1}$-symmetry
including the CuO bond-stretching phonon dispersion is analyzed by a Lorentz
fit in HgBa$_{2}$CuO$_{4}$ and Bi$_{2}$Sr$_{2}$CuO$_{6}$, respectively, using
recently calculated phonon frequencies as input parameters. The resulting mode
frequencies of the fit are almost all in good agreement with the calculated
data. An exception is the second highest $\Delta_{1}$-branch compromising the
bond-stretching modes which disagrees in both compounds with the calculations.
This branch unlike the calculations shows an anomalous softening with a minimum
around the wavevector $\vc{q}=\frac{2\pi}{a}(0.25, 0, 0)$. Such a disparity
with the calculated results, that are based on the assumption of an undisturbed
translation- and point group invariant electronic structure of the CuO plane,
indicates some {\it static} charge inhomogenities in the measured probes. Most
likely these will be charge stripes along the CuO bonds which have the
strongest coupling to certain longitudinal bond-stretching modes that in turn
selfconsistently induce corresponding {\it dynamic} charge inhomogenities. The
symmetry breaking by the mix of dynamic and static charge inhomogenities can
lead to a reconstruction of the Fermi surface into small pockets.

Superconductivity;Materials Science