Upcoming Seminars

"A Salt and Batteries: Applications of Nonresonant Inelastic X-Ray Scattering to Model and Applied Systems," Ken Nagle, University of Washington, hosted by Jorg Maser

Abstract: The rational design of improved electrodes for lithium ion batteries faces many barriers, not the least of which is a correct, fundamental understanding of the changes in electronic structure that accompany insertion and removal of lithium. For this reason, the DOE report "Basic Research Needs for Electrical Energy Storage" singled out nonresonant inelastic X-ray scattering (NIXS) as a promising technique for in situ studies of these basic electrochemical processes. NIXS at ~1-eV energy resolution provides a bulk-sensitive alternative to X-ray absorption spectroscopy for studies of low-energy (<1.5-keV) electronic transitions. Furthermore, at sufficiently high momentum transfer, NIXS is sensitive to dipole-forbidden transitions, providing additional information about electronic structure. After illustrating these issues with a study of Na 1s core excitons in NaCl and NaF, I will discuss the application of NIXS to ex situ and in situ studies of lithiation of transition met!

“Diruthenium Alkynyl Compounds and Their Role in Molecular Electronics,” Tong Ren, Purdue University, hosted by Derrick Mancini

Abstract: Our long-term goal is to achieve both molecular wires and devices based on Ru2-alkynyl species, for which facile charge transfer across the conjugated backbone of Ru2-alkynyl species is the key. Charge transfer properties have been carefully examined in Ru2- alkynyl compounds of extended carbon bridges. Voltammetric and spectroelectrochemical measurements revealed facile electron transfer across both the carbon-rich bridges and the Ru2 fragment. Scanning tunneling microscopy study of Au-bound Ru2(ap)4((C≡CC6H4)2S)- indicated that intrinsic conductance was significantly improved over that of pure organic species of comparable lengths. The current-voltage characteristics of related compounds trans-(S(C6H4C≡C)k)Ru2(ap)4((C≡CC6H4)kS)- was also investigated by using the electromigration break junction technique, and highly reproducible conductance switching was uncovered at low potential bias