Scanning tunneling microscopy with infrared spectroscopy: recent findings.

Surface scientists have used scanning tunneling microscopy (STM) to study the arrangement of molecular-level structures for over thirty years. However, conventional STM images contain limited chemical information, restricting the scope of possible experiments. We extend the functionality of this instrument by combining the strengths of STM with infrared spectroscopy, producing images with both molecular resolution and chemical specificity. We back-irradiated samples, illuminating the adsorbates evanescently. We selected multiplexed photon frequencies using an interferometer. Our model correlates the tunneling current to the vibrational signal. We image chemical structure with molecular resolution. This custom-built instrument performs operates at ambient temperature and pressure, enabling us to run experiments on a variety of systems.