ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The second-harmonic generation (SHG) yield of both evaporated and spin-coated films of some tri-substituted subphthalocyanines has been measured for three linear polarizations of the fundamental beam. Partial molecular ordering in the spin-coated films was achieved by the corona poling technique. For the evaporated films the ordering is obtained through the evaporation process itself. By proper fitting of the SHG yield data and assuming C∞v symmetry the three nonzero independent components, χ31(2), χ15(2) and χ33(2), of the susceptibility tensor have been determined for the two types of films. Kleinman symmetry condition (χ31(2)=χ15(2)) is not obeyed. Values close to 10−9 esu have been obtained for the highest χ31(2) component of the spin-coated films containing trioctylsulfonylsubphthalocyanine molecules. For the evaporated films the susceptibility values are somewhat higher, indicating a significant degree of molecular ordering. For both types of films χ33(2)(very-much-less-than)χ31(2), χ15(2), at variance with the case of linear molecules. From a statistical analysis of the macroscopic SHG emission the nonzero components of the microscopic (molecular) hyperpolarizability tensor, β15, β31 and β33, have also been estimated. The results indicate that β33(approximate)0, and that β31 and β15 are dominant in accordance with the pyramid-shaped molecular geometry. The additional inplane components βyxx=−βyyy=βxxy=−β22 appearing in the C3v molecular symmetry cannot be determined from the macroscopic data. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.369020
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