| The unusual physical properties of linear polyenes, possibility of their simple theoretical description, and high potentials for the future industrial applications attract attention of both theorists and experimentalists. This work reports high resolution optical spectra of the ground and first two excited states of decapentaene and dodecahexaene. The study of vibronic progressions of the obtained electronic spectra provides detailed information about potential surfaces of the ground and excited electronic states and reveals strong vibronic coupling in the first singlet 2;The high lying electronic states of linear polyenes are considered to be critical determinants of unusually high non-linear optical response. Up to date, the information about high lying electronic states was quite limited and insufficient. In this work, the 2-photon excitation spectra of the 3;High resolution optical spectroscopy is very useful method of studying interaction of chromophore molecules with surrounding environment. It has been discovered that the electron-phonon interactions of linear polyenes in n-alkane crystals is strongly dependent on the local symmetry. In the case of centrosymmetric molecule in the centrosymmetric environment the interaction with pseudo-localized phonon is dominant. The pseudo-localized phonon is strongly coupled to the low frequency promoting vibration which is prominent in 1-photon excitation and fluorescence spectra. In the case of disturbed local symmetry the interaction with bulk acoustic phonons is dominant.;The mixed crystals of octatetraene in n-alkane doped with halogenated alkane molecules were used to study the inhomogeneous broadening of the spectral lines. The of dipole moment of the haloalkane molecules, difference in polarizability, and geometrical size allow to study the relative contribution of electrostatic, dispersion and distortion interactions, respectively. The distortion appears to have the largest effect on the inhomogeneous broadening, while dispersion and electrostatic interactions are almost negligible. |
