SURFACE CORE-LEVEL SHIFT FOR LIQUID AND SOLID GALLIUM

Photoelectron spectra of the 3d level of liquid and solid Ga have been measured at temperatures between 295 and 819 K using He II resonance radiation (40.8 eV). A numerical least-squares fit analysis revealed a surface-shifted component of the Ga3d levels for solid Ga with relati ve intensity of 0.25+/-0.03 at -0.22+/-0.02 eV lower binding energy. F or liquid Ga, no such surface-shifted contribution could be detected a t the present level of accuracy. For the Ga3d bulk component (binding energy E(B) = 18.45 eV), a small shift to lower binding energy of DELT AE(B) = -0.018+/-0.005 eV was found in liquid Ga with respect to the r ecrystallized sample.