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Spectral Lineshape, Structural and Dynamics Details of molecular Interfaces with Sub-wavenumber Surface Nonlinear Vibrational Sopectroscopy and Ultrafast Dynamics

Event Details

Event Dates: 

Friday, October 19, 2012 - 10:00am

Speaker Name(s): 

Hongfei Wang

Speaker Affiliation(s): 

Pacific Northwest Laboratory
Seminar Type/Subject

Event Details & Abstract: 

This talk will focus on recent developments in quantitative measurement and interpretation of nonlinear vibrational spectroscopy/dynamics of molecular surfaces and interfaces. For more than two decades, Sum-Frequency Generation Vibrational Spectroscopy (SFG-VS) in the frequency and time domain has been employed to selectively probe structure and dynamics at molecular surfaces and interfaces. The full potential of SFG-VS depends greatly on the ability in making quantitative SFG measurement and interpretation of SFG data in both the frequency and the time domain. Recently, we developed the first sub-wavenumber high resolution broadband SFG-VS (HR-BB-SFG-VS) spectrometer with ~0.6cm-1 spectral resolution and sub 100fs time resolution. The high spectral resolution and excellent line shape thus obtained enabled us to make polarization and phase analysis of the SFG data in accurate determination of molecular species, their orientation and coherent vibrational dynamics of molecular surfaces and interfaces. I will show with several well-studied examples, such as liquid surface, Langmuir and self assembled monolayers, etc., that such development not only enables us to examine quantitatively the models and concepts in surface nonlinear spectroscopy, but also provides new opportunities in studying broad problems at complex surfaces and buried interfaces.