The chemisorption of sulphur on W(100)

The interaction of sulphur vapour with a W(100) surface is studied in detail with Auger Electron Spectroscopy (AES), LEED, work function difference (Δ?) measurements and thermal desorption spectroscopy (TDS). The dissociative adsorption of S occurs on the W surface without reconstruction. Several LEED structures are observed which indicate repulsive adatom interactions. TDS shows that the desorption energy of atomic S decreases from about 8 eV at θ = 0.1 ML to about 3 eV near saturation in close vicinity of 1 ML. Above $\text{θ =}\text{3}\text{4}$ ML, S₂ desorbs in addition to S in a high temperature peak which saturates at about 1 ML. Sulphur in excess of about 1 ML is desorbed in two low temperature peaks of which the lower one consists not only of S and S₂ but also of S₃ and S₄.