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The understanding of lattice instabilities is of vast importance in material science. The famous example is the Peierls instability of one-dimensional metals and for strongly-nested Fermi surfaces in two and three dimensions. Through an analysis of H and Li chains in band theory, we find that the Bloch wave nature of the wavefunctions, if involving strong k-dependent hybridization of oppositeparity atomic states, strongly suppresses susceptibility peaks and associated instabilities and is thus essential to consider in searching for materials with strong responses to external perturbations., Comment: Corrected acknowledgements

The photocorrosion of n‐Cd(Se,Te) electrodes, in potassium and cesium polysulfide solutions, is investigated by x‐ray photoelectron spectroscopy and Auger electron spectrometry. It is shown that Se and Te are exchanged with sulfur from the solution during photocorrosion, possibly via two separate mechanisms: (a) preferential bleaching of tellurium from the crystal matrix, and (b) uniform photocorrosion of the crystal as a whole. Photocurrent spectrum measurements which are presented suggest that a graded band gap is formed when tellurium is preferentially bleached out of the original Cd(Se,Te) crystal. It is shown that cesium is present on the electrode surface which may explain the negative shift of the flat band potential, i.e., increased open circuit voltage of the photoelectrochemical cell. This suggests that the cesium treatment could be used to increase the open circuit voltage of photovoltaic cells.