Development of an experimental set‐up for low‐temperature spectroscopic studies of matrix‐isolated molecules and molecular ices using synchrotron radiation

• Published in: Journal of synchrotron radiation Vol. 25; no. 5; pp. 1425 - 1432
• Main Authors: Singh, Param Jeet, Sundararajan, K., Shastri, Aparna, Kumar, Vijay, Das, Asim Kumar, Kush, P. K., Raja Sekhar, B. N.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.09.2018; John Wiley & Sons, Inc
• Subjects: Absorption spectra; Argon; Fourier transforms; FTIR; FTIR spectrometers; Low temperature; matrix isolation; molecular ices; Photoabsorption; Photochemistry; Photons; Rare gases; Recording; Sulfur dioxide; Synchrotron radiation; VUV spectroscopy; molecular ices; low temperature; matrix isolation; synchrotron radiation; FTIR; VUV spectroscopy
• ISSN: 1600-5775; 0909-0495; 1600-5775
• DOI: 10.1107/S1600577518010482

An experimental set‐up for studying photophysics and photochemistry of molecules in an inert gas medium (matrix‐isolated) and in the ice phase at low temperatures has been developed and commissioned at the Photophysics beamline, Indus‐1 synchrotron radiation source. This end‐station uses an in‐house‐developed closed‐cycle cryostat for achieving cryo‐temperatures (∼10 K). Synchrotron radiation from the Photophysics beamline is used as the source of UV–VUV photons and the system is equipped with a Fourier transform infrared spectrometer for characterization of the molecular species formed at low temperature. Various individual components of the end‐station like closed‐cycle cryostat, experimental chamber, gas mixing and deposition systems are tested to ascertain that the desired performance criteria are satisfied. The performance of the composite system after integration with the Photophysics beamline is evaluated by recording IR and UV–VUV photoabsorption spectra of sulfur dioxide at low temperatures (10 K), both in the ice phase as well as isolated in argon matrices. Results obtained are in good agreement with earlier literature, thus validating the satisfactory performance of the system. As an off‐shoot of the study, the VUV absorption spectrum of matrix‐isolated SO2 in argon matrix up to 10.2 eV is reported here for the first time. This experimental end‐station will provide new opportunities to study photon‐induced reactions in molecules of environmental, astrochemical and industrial importance. Details of the design, development and initial experimental results obtained are presented. The development and commissioning of an experimental set‐up for studying photophysics and photochemistry of molecules in matrix isolation and the ice phase at low temperatures at the Photophysics beamline, Indus‐1, Indian synchrotron radiation source, are reported.