Infrared Reflection Absorption Spectroscopy Setup with Incidence Angle Selection for Surfaces of Non-Metals

• DOI: 10.48550/arxiv.2403.19263
• Publication Date: 2024-03-28
• Authors: David Rath; Vojtěch Mikerásek; Chunlei Wang; Moritz Eder; Michael Schmid; Ulrike Diebold; Gareth S. Parkinson; Jiří Pavelec
• Keywords: Reflection

Infrared Reflection Absorption Spectroscopy (IRAS) on dielectric single crystals is challenging because the optimal incidence angles for light-adsorbate interaction coincide with regions of low IR reflectivity. Here, we introduce an optimized IRAS setup that maximizes signal-to-noise ratio non-metals. This achieved by maximizing light throughput, and selecting directly impact peak heights in spectra. The uses a commercial FTIR spectrometer usable ultra-high vacuum (UHV). Specifically, design features sample illumination collection mirrors high numerical aperture inside UHV system, adjustable to select angle range sample. important p-polarized measurements dielectrics, peaks spectra reverse direction at Brewster (band inversion). system components are connected precisely via flange, ensuring long-term stability. We studied (SNR) variation one monolayer CO TiO2(110) as function range, where maximum 70 was 4 cm-1 resolution five minutes measurement time. capabilities s-polarization demonstrated measuring D2O adsorbed surface, SNR 65 delta_R/R0 height 1.4x10-4 twenty minutes.