Instrumental Development: Infrared Multiphoton Dissociation Spectroscopy in a Cold Ion Trap

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With support from the Chemistry Research Instrumentation and Facilities: Instrument Development (CRIF:ID) Program, Professors Roger Miller, Tomas Baer, and Gary Glish of the University of North Carolina at Chapel Hill will develop a state-of-the-art infrared laser system and cooled ion-trap mass spectrometer for infrared multiphoton dissociation (IRMPD) spectroscopy. This new instrument will enable high-resolution IR spectroscopy of molecular ions, which is currently only available using very expensive equipment such as free-electron lasers at multi-user facilities. The project will combine the expertise of Miller's group in developing IR lasers with the Glish group's experience building ion-trap mass spectrometers. Baer will add a complementary level of theoretical expertise to interpret experimental photoelectron spectra.The new instrumentation will use new optical parametric oscillator technology to obtain a wide tunability and a build-up cavity to achieve high power. The quadrupole ion trap will use an electrospray ionization source and will be cooled with a closed-cycle cryogenic refrigerator. The IR spectra that the instrument will be able to record will be used by the PIs to make progress in using spectroscopy to determine secondary structures of polypeptides and proteins. Other work will include gas-phase studies of ion solvation, metal binding in biomolecules, and studies of ion dissociation dynamics.A postdoctoral associate and a graduate student will do the bulk of the instrument development. Once constructed, it will be available as an advanced tool for approximately 30 students and postdocs in the three research groups. The PIs will also make the instrument accessible to collaborators and will disseminate results to aid others in developing similar instruments. This laboratory-scale instrumentation will greatly expand the accessibility to high-resolution IRMPD spectroscopy, which could have a large impact in a variety of scientific fields. Extending use of the instrument to more applied areas such as interrogation of large biomolecules is anticipated by the PIs.