Spectral properties of polycyclic aromatichydrocarbons (PAHS) and astrophysical investigation of them

The polcyclic aromatic hydrocarbons (PAHs) can be observed in astrophysical environments like interstellar medium, circumstellar matter around the evolved stars, planetary nebulae and planetary atmospheres. Bands that are thought to originate from PAHs are observed in the infrared spectra taken from these environments.. PAHs, which are thought to have critical roles in the emergence of life on Earth, are also an important research subject in astrobiology. In this thesis, PAH molecules and their spectral properties have been examined. In order to investigate the spectral properties and profiles of PAHs, "The Nasa Ames PAH IR Spectroscopic Database" developed by NASA, has been used. Expected spectral profiles of a total of 32 PAH molecules, selected in different sizes, shapes and charges, have been derived for the infrared region covering the range of 0 - 15 µm. These profiles were obtained especially by considering the physical conditions of the material surrounding the evolved stars and assuming that they were produced in these environments. Derived spectral profiles were examined to understand how the size, shape and charge of the molecules and temperature of the environment affect these profiles.