Publication: IEICE TRANSACTIONS on Electronics Publication Date: 2004/12/01 Vol. E87-CNo. 12pp. 2108-2111 Type of Manuscript: Special Section PAPER (Special Section on Recent Progress in Organic Molecular Electronics) Category: Evaluation Methods and Characterization of Organic Materials Keyword: PTCDA, organic thin film, photoacoustic spectra, PAS, non-radiative process,