Adsorption and temperature-dependent decomposition ofSO2on Cu(100) and Cu(111): A fast and high-resolution core-level spectroscopy study

The adsorption and temperature-dependent decomposition of ${\mathrm{SO}}_2$ on Cu(100) and Cu(111) have been studied by fast and high-resolution core-level photoemission. The analysis of the S 2p and O 1s data shows that molecular ${\mathrm{SO}}_2$ adsorption dominates at 170 K. On heating the ${\mathrm{SO}}_2$-covered surfaces to about room temperature, ${\mathrm{SO}}_2$ decomposes into SO+O+S. On further heating SO+O recombine to form ${\mathrm{SO}}_2$, which is the only species detected in corresponding temperature-programmed desorption (TPD) experiments. From the temperature- (time-) dependent S and O coverages a ‘‘TPD curve’’ can be constructed. © 1996 The American Physical Society.