Electroreflectance spectra of polycrystalline gallium in alkali solutions

The electroreflectance spectra (ES) of polycrystalline gallium in alkali so lutions have two bands of charge transfer (BCT) from adsorbed water molecul es to metal. The energy of one band equals about 4.6 eV and is potential-in dependent, which points to the presence of water molecules with a zero char ge transfer at the metal surface. The energy of the other is lower and drop s with increasing potential, which points to the absence of decomposition o f adsorbed water to OH- groups. The plasma ES on gallium is determined larg ely by mechanism governing electromodulation of the concentration of the su rface anion centers where the metal's free electrons are scattered. The mec hanism provides the ES intensity commensurate with that of the water BCT.