Event DetailsEvent Dates: Friday, January 19, 2018 - 4:00pmSeminar Location: JILA AuditoriumSpeaker Name(s): Alexander BenderskiiSpeaker Affiliation(s): University of Southern California Seminar Type/SubjectScientific Seminar Type: Phys Chem/Chem Phys SeminarEvent Details & Abstract: 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 molecular, 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 the interface.