Adding a dimension to the infrared spectra of interfaces using heterodyne detected 2D sumfrequency generation (HD 2D SFG) spectroscopy

Wei Xiong, Jennifer E. Laaser, Randy D. Mehlenbacher, Martin T. Zanni

Research output: Contribution to journalArticlepeer-review

120 Scopus citations

Abstract

In the last ten years, two-dimensional infrared spectroscopy has become an important technique for studying molecular structures and dynamics. We report the implementation of heterodyne detected two-dimensional sum-frequency generation (HD 2D SFG) spectroscopy, which is the analog of 2D infrared (2D IR) spectroscopy, but is selective to noncentrosymmetric systems such as interfaces. We implement the technique using mid-IR pulse shaping, which enables rapid scanning, phase cycling, and automatic phasing. Absorptive spectra are obtained, that have the highest frequency resolution possible, from which we extract the rephasing and nonrephasing signals that are sometimes preferred. Using this technique, we measure the vibrational mode of CO adsorbed on a polycrystalline Pt surface. The 2D spectrum reveals a significant inhomogenous contribution to the spectral line shape, which is quantified by simulations. This observation indicates that the surface conformation and environment of CO molecules is more complicated than the simple "atop" configuration assumed in previous work. Our method can be straightforwardly incorporated into many existing SFG spectrometers. The technique enables one to quantify inhomogeneity, vibrational couplings, spectral diffusion, chemical exchange, and many other properties analogous to 2D IR spectroscopy, but specifically for interfaces.

Original languageEnglish (US)
Pages (from-to)20902-20907
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number52
DOIs
StatePublished - Dec 27 2011

Keywords

  • CO monolayer
  • Multidimensional spectroscopy
  • Pt catalysis
  • Surface-sensitive
  • Vibrational spectroscopy

Fingerprint Dive into the research topics of 'Adding a dimension to the infrared spectra of interfaces using heterodyne detected 2D sumfrequency generation (HD 2D SFG) spectroscopy'. Together they form a unique fingerprint.

Cite this