THIN-LAYERS OF ALUMINUM - A MOLECULAR-ORBITAL STUDY

Molecular beam epitaxy has been used to prepare thin layers (200 nm th ickness) of aluminium grown either on aluminium or gallium arsenide su bstrates; their He(I) and He(II) photoelectron spectra have been recor ded. The quasirelativistic CNDO/1 method has been applied to investiga te the band structure of {Al}172, {Al}284 and {Al}424 clusters obtaine d by a duplication of the unit cell: the DOS profiles and their projec tions were generated. These data were correlated with the periodic cry stal orbitals of the EHT quality. The first excitation energy serves a s a better estimate of the vanishing energy gap showing thus a metalli c character of aluminium.