A comparison of ground- and excited-state properties of gas phase and crystalline ruthenocene using density functional theory

The ground- and excited-state properties of both gas phase and crystalline ruthenocene, Ru(cp)2, are investigated using density functional theory. A symmetry-based technique is employed to calculate the energies of the multiplet splittings of the singly excited triplet states. For the crystalline system, a Buckingham potential is introduced to describe the intermolecular interactions between a given Ru(cp)2 molecule and its first shell of neighbors. The overall agreement between experimental and calculated ground- and excited-state properties is very good as far as absolute transition energies, the Stokes shift and the geometry of the excited states are concerned. An additional energy lowering in the 3B2 component of the 5a1[prime] --> 4e1[double-prime] excited state is obtained when the pseudolinear geometry of Ru(cp)2 is relaxed along the low-frequency bending vibratio