The electronic structure of high-quality TiSe2 and TiS2 crystals has been investigated using angle-resolved photoemission with Hei, Hen, and Nei resonance radiation. Results compare well with recent selfconsistent energy-band calculations although differences occur which may be due to the threerather than two-dimensional nature of specific bands. Occupied d states at the zone edge are observed in both materials.A small overlap with the s/p valence band at I is observed in the case of TiSe, in approximate agreement with other workers. TiS, appears to be a defect semiconductor with a band gap of 0.3+0,2 eV.

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Electron-beam-induced decomposition of trimethylamine (.CH 3 / 3 N) adsorbed on the Si(100)-2 × 1 surface has been investigated using temperature-programmed desorption, electron-stimulated desorption, timeof-flight mass spectrometry, and x-ray photoelectron spectroscopy. At issue is the cleavage of C-H bonds vs. cleavage of N-C bonds in the dissociation of trimethylamine (TMA), which is a dative-bonded adduct on the Si dimer. Methyl groups are cleaved from the adsorbed TMA by electron irradiation. In addition, hydrogen is desorbed from the TMA and/or its fragments, which influences the decomposition of the TMA to smaller adsorbed fragments. The appearance of a thermal desorption peak for mass 42 subsequent to electron irradiation suggests the production of reaction intermediates similar to those reported previously in gas-phase decomposition of TMA at high temperature.

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