Absorption coefficient of sexithiophene thin films grown by organic molecular beam deposition

Several films with different thickness of both beta -methyl sexithiophene a nd unsubstituted sexithiophene were grown on fused silica by organic molecu lar beam deposition in ultra-high vacuum conditions and their optical absor ption properties were investigated. Because of the different molecular arra ngement of the two materials, different optical spectra are observed. By co mparing the absorbance spectra of samples of different thickness, the absor ption coefficients of both beta -methyl sexithiophene films and sexithiophe ne films were deduced.