Department of Chemistry at the University of Virginia

Frederick S. Richardson

Commonwealth Professor of Chemistry
B.S. Dickinson College, 1961
Ph.D., Princeton University, 1966
Postdoctoral, University of California, San Diego, 1968-69
Camille and Henry Dreyfus Teacher-Scholar, 1973-78
Email Frederick S. Richardson
Phone: (434) 924-3905

Atomic and Molecular Spectroscopy; Chirality Dependent Molecular Dynamics and Recognition; Lanthanide Chemistry and Spectroscopy; Optical Studies of Biomolecular Systems.

Much of our present research focuses on the spectroscopic properties, electronic structure, and coordination chemistry of lanthanide ions in solution and in the solid state. The lanthanide elements exhibit remarkably diverse optical and magnetic properties across the lanthanide series (from cerium to ytterbium). These properties may be understood largely in terms of the electronic states split out of the 4fN (N=1-13) electronic configuration, and when a lanthanide ion resides in a ligand or crystalline environment these properties depend on the details of the lanthanide-ligand (or crystal) interactions.

nderstanding these interactions and their influence on the 4fN electronic states is important to designing lanthanide-based materials with specific optical and magnetic properties and is essential to fully rationalizing the very complex electronic spectra exhibited by most lanthanide systems. In our research, we study the optical and magneto-optical properties of lanthanide systems using a variety of spectroscopic techniques, and then analyze the empirically characterized properties using theoretical models designed to correlate the spectroscopic observables with specific electronic and structural parameters of the systems. These parameters reflect interactions within the 4fN electronic configuration, lanthanide-ligand interactions, and coordination number and geometry, and they may be correlated with transition energies and intensities, excited state lifetimes, energy transfer efficiencies, and both ground and excited state magnetic properties. Systematic characterizations of these parameters yield information essential to the rational design of lanthanide systems with pre-specified optical and magnetic properties, and they are necessary in selecting lanthanide ions to be used as spectroscopic probes of biomolecular structure and function.

Structural chirality in molecules and crystals, chiral interactions between molecules, and various chiroptical spectroscopies are also of major interest in our research program. We recently developed instrumentation for measuring time-resolved circularly polarized luminescence (TR-CPL) and have also developed techniques for measuring the optical activity of molecular enantiomers in racemic mixtures. With TR-CPL, we can study excited-state stereochemical dynamics and we can also probe enantioselective interactions between chiral molecules optically prepared in a variety of electronic excited states. This technique has also proved useful in characterizing chiral discrimination in electronic energy-transfer processes. The mechanistic basis of chiral recognition and discrimination processes in chemistry remains poorly understood, and much of our experimental and theoretical work is directed towards improving our fundamental understanding of these processes.

Representative Publications

Excited-state enantiomer interconversion kinetics probed by time-resolved chiroptical luminescence spectroscopy. The solvent and temperature dependence of Λ-Eu(dpa)₃^3-⇔ Δ-Eu(dpa)₃^3- enantiomer interconversion rates in solution. D.P. Glover-Fischer, D.H. Metcalf, T.A. Hopkins, V.J. Pugh, S.J. Chisdes, and F.S. Richardson. Inorg. Chem. 1998. 37: 3026-3033.

Chiroptical absorption and luminescence spectra of a dissymmetric osmium(II)-polypyridyl complex containing an optically active bisbipyridine-type ligand of well-defined structural chirality. K.E. Gunde, A. Credi, and F.S. Richardson. Inorg. Chem. 1997. 36: 426-434.

Energy transfer and up-conversions in cubic Cs₂NaYCl₆:Er³⁺ and Cs₂NaErCl₆. Z, Hasan, L. Biyikli, M.J. Sellars, G.A. Khodaparast, J.R. Quagliano, and F.S. Richardson. Phys. Rev. B. 1997. 56: 4518-4528.

Intermolecular chiral recognition probed by enantiodifferential excited-state quenching kinetics. T. Gowl Stockman, C.A. Klevickis, C.M. Grisham, and F.S. Richardson. J. Molecular Recognition. 1996. 9: 595-606.