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Polarized resonance Raman spectra of an oriented diphenylpolyene
Author(s) -
Margulies L.,
Stockburger M.
Publication year - 1979
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250080107
Subject(s) - tensor (intrinsic definition) , anisotropy , resonance (particle physics) , raman spectroscopy , molecular physics , excitation , diagonal , raman scattering , spectral line , asymmetry , scattering , chemistry , nuclear magnetic resonance , atomic physics , physics , optics , quantum mechanics , geometry , mathematics
Measurements of polarized Raman intensities of partially oriented molecules were shown to be useful for obtaining information about the components of the scattering tensor and the degree of orientation in anisotropic samples. The polarized resonance Raman (RR) spectra of all‐ trans ‐1,14‐diphenyltetradecaheptaene (DPTH) incorporated in a stretched polyethylene film were studied. The DPTH molecules are highly oriented in the polymer matrix with their longitudinal axis in the direction of stretching. The different components of the scattering tensor for the totally symmetric vibrations of DPTH were determined in the case of resonance excitation. It was found that the diagonal element α zz (z is defined along the polyene chain) gives the largest contribution to the RR intensity. However, the two off‐diagonal elements α zy and α yz also contribute significantly and have different magnitudes. The physical origin of these off‐diagonal elements and of the asymmetry of the scattering tensor are discussed in terms of the vibronic coupling theory.