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Abstract:

Linear spectroscopies, ranging from electronic to Raman and infra-red, are the workhorse methods used to interrogate time and energy scales of chemical systems. However, in disordered condensed phase systems the presence of many overlapping features makes decoding the information present to obtain the individual processes and states present, the timescales of their interconversion, and the molecular motions they arise from extremely challenging. Nonlinear spectroscopies provide much richer information, with the 2D counterparts of the aforementioned spectroscopies (2D-ES, 2D-Raman and 2D-IR) giving access to extra time and frequency dimensions that allow for easier identification of the states present and the rates of their interconversion. However, while these methods yield information on the timescales present in condensed phase chemical systems, linking these to the microscopic structural changes that give rise to them often poses a significant challenge. In this talk I will discuss our recent work using ab initio path integral simulations, which incorporate the quantum mechanics of the electrons and nuclei, to understand the 2D-IR of proton defects in aqueous solution. I will then discuss our work on developing the theory and interpretation of recently developed impulsive nuclear Raman and x-ray scattering (INXS) experiments which provide a new route to image molecular-scale structure and dynamics in disordered media.

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Bio:

Professor Tom Markland鈥檚 research interests lie broadly in the development of theoretical and simulation approaches and their application to explain effects observed in the classical and quantum dynamics of chemical systems. Tom received his MChem in Chemistry from Balliol College, University of Oxford where he was a Brackenbury Scholar and did his thesis work in the area of non-adiabatic dynamics. He continued at Oxford for his DPhil research in the area of quantum dynamics under the supervision of Professor David Manolopoulos. In 2009 he was awarded the Royal Society of Chemistry's Coulson Prize. After postdoctoral work with Professor Bruce Berne at Columbia University he moved to Stanford in 2011 as an Assistant Professor in the Department of Chemistry. In 2018 he was promoted to Associate Professor with tenure. Since starting at Stanford he has been awarded a Research Corporation Cottrell Scholarship, Alfred P. Sloan Research Fellowship, Terman Fellowship, Hellman Faculty Scholarship, the ACS OpenEye Outstanding Junior Faculty Award, the NSF CAREER award, the Camille Dreyfus Teacher-Scholar award, the H&S Dean's Award for Distinguished Teaching, the Kavli Emerging Leader in Chemistry Lectureship, and the ACS Early Career Award in Theoretical Chemistry.