Events

April 1, 2018 at 11:30 pm

Chemistry Colloquium | Molecular Orientation and Hydrogen Bonding at Aqueous Interfaces, April 2

Ohio University’s Chemistry & Biochemistry Colloquium Series presents Dr. Alexander Benderskii on, Molecular Orientation and Hydrogen Nonding at Aqueous Interfaces on Monday, April 2, at 4:10 p.m. Clippinger Laboratories 194.

Dr. Alexander Benderskii, photo taken in lab

Dr. Alexander Benderskii

Benderskii is Associate Professor of Chemistry at the University of Southern California.

Abtract:  Physical and chemical properties of interfacial water affect processes such as heterogeneous catalysis, electrochemistry, atmospheric, environmental chemistry, and biological self-assembly.  The two sides of the puzzle describing water properties on the microscopic scale are hydrogen bonding and molecular orientation.  Both of these reflect the asymmetry of the interfacial environment.  In this talk, I will discuss applications of the surface-selective vibrational sum frequency generation (VSFG) spectroscopy to address the interplay between H-bonding and alignment of the water molecules at the air/water interface, and in the presence of electric field at charged interfaces such as organic monolayers or transparent electrodes.

Both vibrational modes of water (stretch and bend) were spectroscopically investigated by VSFG.  We will discuss the spectral line shapes and polarization dependence of the VSFG spectra to extract the molecular orientation.  Comparison of the stretch and bend spectra, together with theoretical calculations by our collaborators, aid the assignment of the spectral features to different hydrogen bonding motifs.  Furthermore, polarization-dependent measurements of the stretch and bend vibrational modes are complementary, because their transition dipoles have different orientations in the molecular frame.  Together, they help us understand the 3-dimensional orientation of the water molecules at interfaces.

 The host is: Dr. Katherine Cimatu

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