title: High-resolution electron spectroscopy of lanthanide (Ce, Pr, and Nd) complexes of cyclooctatetraene: the role of 4f electrons.
abstract: Cerium, praseodymium, and neodymium complexes of 1,3,5,7-cyclooctatetraene (COT) complexes were produced in a laser-vaporization metal cluster source and studied by pulsed-field ionization zero electron kinetic energy spectroscopy and quantum chemical calculations. The computations included the second-order Møller-Plesset perturbation theory, the coupled cluster method with single, double, and perturbative triple excitations, and the state-average complete active space self-consistent field method. The spectrum of each complex exhibits multiple band systems and is assigned to ionization of several low-energy electronic states of the neutral complex. This observation is different from previous studies of M(COT) (M = Sc, Y, La, and Gd), for which a single band system was observed. The presence of the multiple low-energy electronic states is caused by the splitting of the partially filled lanthanide 4f orbitals in the ligand field, and the number of the low-energy states increases rapidly with increasing number of the metal 4f electrons. On the other hand, the 4f electrons have a small effect on the geometries and vibrational frequencies of these lanthanide complexes.
authors: Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA.
authors: Sudesh
authors: S
authors: Kumari
authors: Mourad
authors: M
authors: Roudjane
authors: Dilrukshi
authors: D
authors: Hewage
authors: Yang
authors: Y
authors: Liu
authors: Dong-Sheng
authors: DS
authors: Yang
mesh_terms: D034242:Cyclooctanes / Q000737:chemistry*; D004583:Electrons; D007700:Kinetics; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D013057:Spectrum Analysis
chemical_list: D034242:Cyclooctanes; D028581:Lanthanoid Series Elements; D009942:Organometallic Compounds; C534209:1,3,5,7-cyclooctatetraene