This talk will review applications of the surface-selective vibrational sum frequency generation (SFG) spectroscopy to study molecular structure, orientation, conformation, and rotational dynamics at chemically functionalized surfaces. Examples will include alkane-thiol self-assembled monolayers (SAMs) functionalized with azobenzene moieties that can undergo switching by photoisomerization, and methyl-terminated silicon surfaces.  Polarization-selected SFG allows us to measure orientation of the functional groups and follow it in real time, thus reporting on the rotational and photoisomerization dynamics.  Steric hindrance of photoisomerization is observed in azobenzene SAMs when azobenzene moieties are close-packed.  Hindered propeller-like rotation of the methyl groups at room temperature is observed on methyl-terminated silicon (111) surfaces.

Structure and dynamics at chemically functionalized surfaces

247th National Meeting (2014)

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