IR, Raman, and UV/Vis spectra of corannulene for use in possible interstellar identification.

ABSTRACT

The spectroscopic characterization of corannulene (C(20)H(10)) is carried out by several techniques. The high purity of the material synthesized for this study was confirmed by gas chromatography-mass spectrometry (GC-MS). During a high-performance liquid chromatography (HPLC) process, the absorption spectrum of corannulene in the ultraviolet (UV) and visible (vis) ranges is obtained. The infrared (IR) absorption spectrum is measured in CsI pellets, and the Raman scattering spectrum is recorded for pure crystal grains. In addition to room temperature measurements, absorption spectroscopy in an argon matrix at 12 K is also performed in the IR and UV/Vis ranges. The experimental spectra are compared with theoretical Raman and IR spectra and with calculated electronic transitions. All calculations are based on the density functional theory (DFT), either normal or time-dependent (TDDFT). Our results are discussed in view of their possible application in the search for corannulene in the interstellar medium.