Abstract
Since the unidentified infrared (UIR) bands were observed from wide variety of objects in the Galaxy and in the extragalactic regions, the carriers of these bands could be the clue to understand the evolution of interstellar matters. Polycyclic aromatic hydrocarbons (PAHs) have been considered most plausible candidates of the UIR bands. During the formation and growth of PAH clusters, PAHs may be undergone plasma environments. Since the effects of plasma on the formation of PAH clusters have never been elucidated, we tried to produce PAH clusters in a plasma field and measure their infrared spectra for understanding the plasma effects on the PAHs. We discuss the effects of plasma and the carrier of the UIR bands by comparing the spectroscopic data and the UIR bands.
