  This work reports a 'Density Functional Theory' (DFT) calculation of PAH
molecules with a five-member ring to determine the expected region of infrared
features. It is highly possible that fullerene molecule might be originated
from five-membered ring PAH molecules in the ISM. Effect of ionization and
protonation on five-membered ring PAH molecule is also discussed. A detail
vibrational analysis of five-membered ring PAH molecule has been reported to
further compare with observations and to identify any observational
counterpart.
