Lifting of Accidental Degeneracy in Molecular Vibrations Probed with Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy

ORAL

Abstract

Ultrahigh Vacuum Tip-enhanced Raman spectroscopy (UHV-TERS) combines the imaging capability of scanning probe microscopy (SPM) with the single-molecule chemical sensitivity of surface-enhanced Raman spectroscopy (SERS). In combination with time-dependent density functional theory (TDDFT), insights into the influence of intermolecular interactions on the vibrational spectra of a N-N'-bis(2,6-diisopropylphenyl)-perylene-3,4:9,10-bis(dicarboximide) (PDI) self-assembled monolayer is revealed. In particular, we have interrogated the lifting of an accidental vibrational degeneracy of a mode of PDI on Ag(111) and Ag(100) surfaces, with the most strongly perturbed mode being that associated with the largest vibrational amplitude on the periphery of the molecule. This work demonstrates that UHV-TERS enables direct measurement of molecule-molecule interaction at nanoscale.

*We acknowledge supports from the National Science Foundation Center for Chemical Innovation dedicated to Chemistry at the Space−Time Limit Grant CHE-1414466, and the Department of Energy Office Grant DE-FG02-09ER16109).

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Presenters

  • Naihao Chiang

    • Northwestern Univ.

Authors

  • Naihao Chiang

    • Northwestern Univ.

  • Nan Jiang

    • Univ. of Illinois at Chicago

  • Lindsey Madison

    • Northwestern Univ.

  • Eric Pozzi

    • Northwestern Univ.

  • Mark Ratner

    • Chemistry, Northwestern University
    • Northwestern Univ.
    • Northwestern University

  • Mark Hersam

    • Department of Material Science, Northwestern University
    • Northwestern Univ.
    • Department of Materials Science and Engineering, Northwestern University
    • Materials Science and Engineering, Northwestern University

  • Tamar Seideman

    • Northwestern Univ.

  • George Schatz

    • Northwestern Univ.
    • Chemistry Department, Northwestern University
    • Department of Chemistry, Northwestern University

  • Richard Van Duyne

    • Northwestern Univ.