15 cm$^{-1}$ to 12000 cm$^{-1}$ spectral coverage without changing optics: diamond beam splitter adaptation of an FTIR spectrometer

Abstract: In order to facilitate IR absorption measurements of mass-selected ions isolated in cryogenic matrices, we have upgraded an ion beam deposition apparatus encompassing a Bruker IFS66v/S FTIR spectrometer. A synthetic diamond beam splitter without compensator plate and UHV diamond viewports were installed. We have also modified the IR detector chamber to allow measurements with 5 different detectors. As a result we can now obtain FT absorption spectra from 12000 cm$^{-1}$ to 15 cm$^{-1}$ with the same sample held under ultrahigh vacuum conditions, simply by switching between appropriate IR detectors. We demonstrate performance of the upgraded FTIR spectrometer by presenting measurements of matrix isolated fullerene ions and an adhesive tape.