Variable photon energy photoelectron spectroscopy of tris-cyclopentadienyl lanthanides.

The gas phase photoelectron (PE) spectra of LnCp3 (Cp = η-C5H5; Ln = Pr, Nd, Sm), measured with a wide range of photon energy, are reported. Resonances observed in the photon energy regions of 4d to 4f excitation enable identification of ion states resulting from 4f ionization. For all three compounds molecular ion states characteristic of both 4f(n) and 4f(n-1) configurations are observed (Pr, n = 2; Nd, n = 3; Sm, n = 6).