CaSTL Seminar Series and the Center for Chemical Innovation presents: Matthew Sheldon, Texas A&M University
Matthew T. Sheldon received his BA from Carleton College (Chemistry), PhD from UC Berkeley (Chemistry), and performed his postdoc at Caltech (Mat.Sci/App.Phys). He is the recipient of the 2015 Air Force Office of Scientific Research Young Investigator Program (AFOSR YIP) Award, the Kaneka Junior Faculty Award (2017), and was selected as a 2017 Inventor Fellow by the Gordon and Betty Moore Foundation.
Abstract: X-ray absorption near edge spectroscopy (XANES or NEXAFS) is a powerful technique for electronic structure determination. However, widespread use of XANES is limited by the need for synchrotron light sources with tunable x-ray energy.
Ultrahigh vacuum tip-enhanced Raman spectroscopy (UHV-TERS) is used to investigate adsorption of molecular oxygen (O2) with cobalt (II) phthalocyanine (CoPc) supported on Ag(111) single crystal surfaces, which is the initial step for the oxygen reduction reaction (ORR) using metal Pc catalysts. Two adsorption configurations are primarily observed, assigned as O2/CoPc/Ag(111) and O/CoPc/Ag(111) based on scanning tunneling microscopy (STM) imaging, TERS, isotopologue substitution, and density functional theory (DFT) calculations.
Investigation of molecular dynamics with sufficient time and spectral resolution is very crucial for understanding the mechanistic aspects of any photophysical and photochemical process. In this seminar, I will briefly discuss about the femtosecond transient absorption technique and then introduce with the ultrafast Raman loss spectroscopic (URLS) technique that is analogous to femtosecond stimulated Raman scattering (FSRS) spectroscopy. These spectroscopic techniques (URLS/FSRS) offer excellent frequency and time resolution to decipher molecular dynamics at ultrafast timescales.
Molecular interfaces play a dominant role in much of Chemistry, and are of vital importance in diverse applications such as sensing, catalysis and electron transfer. Yet the mere fact of coupling two fundamentally different materials, e.g.