Mid-infrared vibrational study of deuterium-containing PAH variants
  Polycyclic Aromatic Hydrocarbon (PAH) molecules have been long proposed to be
a major carrier of 'Unidentified Infrared' (UIR) emission bands that have been
observed ubiquitously in various astrophysical environments. These molecules
can potentially be an efficient reservoir of deuterium. Once the infrared
properties of the deuterium- containing PAHs are well understood both
experimentally and theoretically, the interstellar UIR bands can be used as a
valuable tool to infer the cause of the deuterium depletion in the ISM.
  Density Functional Theory (DFT) calculations have been carried out on
deuterium-containing ovalene variants to study the infrared properties of these
molecules. These include deuterated ovalene, cationic deuterated ovalene,
deuteronated ovalene and deuterated-deuteronated ovalene. We present a D/H
ratio calculated from our theoretical study to compare with the observationally
proposed D/H ratio.
