Donor-acceptor substituted linear polyenes: Chain length dependent electronic structure of anthrylpolyenes J. Chem. Phys. 98, 7969 (1993); 10.1063/1.464551 Resonant Raman scattering of controlled molecular weight polyacetyleneWe have measured the solid state Raman scattering spectra of a homologous series of linear polyenes, with the number of alternated double bonds varying from 3 to 12. While we find a linear dependence of the Raman shifts of resonantly coupled modes with inverse conjugation length, we have also followed the suggestion of previous work in examining the inverse square product of the several Raman frequencies as a function of the logarithm of the measured energy gap of the molecule. This provides a linear relationship, as found for transpoly acetylene, a result which is qualitatively consistent with the amplitude mode model of Horovitz and co-workers. We also find, consistent with previous work on polyacetylene, a monotonic decrease in the ratios of oscillator strengths of the two strongest bands with conjugation length, as recently predicted by a series of molecular dynamics calculations. Suggested interpretations of a number of qualitative observations, including splitting of modes for shorter conjugation length, are offered, and the implications for the structure of transpolyacetylene are discussed. The present work confirms that the previously measured dispersion in the Raman spectra of trans-polyacetylene is due to a distribution of conjugation lengths and brings into question some of the quantitative aspects of the amplitude mode model.

No abstract

No abstract

Mechanism of CO oxidation reaction on O-covered Pd (111) surfaces studied with fast x-ray photoelectron spectroscopy: Change of reaction path accompanying phase transition of O domains

No abstract