THE PRODUCTION AND UV PHOTODISSOCIATION OF IRON-SULFUR BINARY CLUSTERS

The iron-sulfur cluster cluster ions; FenSm+ (n = 1 - 13, m = 1 - 13), were produced by diredt laser vaporization of a solid sample containing a mixture of iron and sulfur powder. UV photodissociation of the cluster ons was studied with a tandem time-of-flight mass spectrometer. It was found that all the cluster ions with compositions of m = n, m = n - 1 or m = n + 5 have relatively larger abundances, indicating that they were more stable. The photodissociation results of FenSm+ ions showed that when n approximate to m, the main channels were losses of neutral S atoms until n approximate to m, while for parent ions with n approximate to m, the main product ions have the m = n or m = n - 1 compositions. Form these experimental results, it was proposed that the FenSm+ ions might have structures similar to those of FenSn cores in iron-sulfur protiens, while the structures of the FenSm+(m > n) cluster ions could be considered to have a pattern of the FenSm+ cores with some peripheral S atoms