Vibrational Sum Frequency Generation Spectrometer
Technical Report,18 Apr 2016,17 Apr 2017
University of Iowa at Iowa City Iowa City United States
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Major Goals The major goal of this project was to purchase and install a tunable infrared, vibrational sum frequency generation vSFG spectrometer to benefit the research and teaching missions of the University of Iowa and neighboring institutions. There are several other groups in the U.S. that use vSFG to investigate interfacial phenomena, such as spontaneous organization of lipid bilayers, surfactancy, or mechanisms of heterogeneous catalysis. However, there was not a vSFG spectrometer available in the state of Iowa. This proposal aimed to provide researchers in this region access to vSFG, enabling higher quality research. The spectrometer is composed of a visible beam at 532 nm and tunable infrared laser. The spectrometer includes optics to direct these two beams to our sample substrates, where the photons are up-converted to the sum-frequency sum ir vis. Sum-frequency photons are analyzed for polarization, selected for wavelength, and quantified by a photomultiplier tube. By scanning the wavelength of incident IR photons and monitoring intensity of the energy-matched SFGphotons, an effective vibrational spectrum of exclusively interfacial species may be acquired. This spectrometer is turn-key including all optics, electronics, software, detection monochromator, and laser table. Accomplishments All major goals are accomplished. The vSFG spectrometer is purchased and installed in our laboratory. Preliminary data using the SHG and vSFG modes of the instrument are attached to this report via the uploaded file for two projects. These data serve two research projects in my group. One is the interrogation of solid ionic liquid interfaces. This project includes thin ca. 1 m films of ILs on metallic substrates, allowing unprecedented spectroscopic measurements of the interface and surface-induced phase transitions.
- Test Facilities, Equipment and Methods