Aluminumndash;sulfur cluster ions: Formation and photolysis

摘要

Aluminumndash;sulfur cluster ions were obtained by direct laser ablation (248 nm, ge;10 MW/cm2) and analyzed with a tandem timehyphen;ofhyphen;flight mass spectrometer. The regular peaks of cluster ions having composition of AlS+(Al2S3)n(n=1,2,3,...,31) were shown on the first timehyphen;ofhyphen;flight mass spectrum (TOFhyphen;MS). The cluster ions of a certain mass number (m/e) could be selected and photolyzed by an ArF laser (193 nm, 1 MW/cm2). The product ions were analyzed by a second TOFhyphen;MS. It was found that the cluster ions lost (Al2S3)x(x=1, 3, or 4) and became smaller cluster ions of the same stable formula AlS+(Al2S3)nminus;x. Cagelike structures were proposed to be possible for these stable cluster ions. Semiempirical andabinitioquantum chemical calculations have also been performed for some of the clusters.