Vacuum ultraviolet photoionization and photodissociation of ferrocene

摘要

Photoionization and photodissociation of ferrocene [Fe(C_5H_5)_2] is examined by using vacuum ultraviolet (VUV) photons from a synchrotron radiation source and a time-of-flight (TOF) photoionization mass spectrometer. VUV absorption by ferrocene results in Fe(C_5H_5)_2~(·+), FeC_5H_5~+, FeC_3H_3~+, Fe~(·+) and C_(10)H_x~(·+) (x = 8 - 10). The dependency of the product distribution on photon energy indicates sequential elimination of C_5H_5· via two channels. One is nonstatistical dissociation with a fast rate, and the other is slow unimolecular decay that becomes more discernible at low photon energy. The rate of unimolecular decay, exemplified by a value of k = 2.4 ± 1.0 * 10~6 s~(-1) at photon energy of 14.76 eV, is well in accord with the RRKM rate.