Temperature dependence of optical spectra of bacteriochlorophyll a in solution and in low-temperature glasses
Article Abstract:
The optical spectra of bacteriochlorophyll a in solution and in low-temperature glasses have been investigated under different temperatures. Results show changes in the absorption spectra that take place continuously throughout the temperature range from 298 to 79 K indicates a possible increase in the extent of coordination of the central Mg, changes in solvent dielectric and/or modified hydrogen bonding. Fluorescence emission spectra, on the other hand, contains 1-propanol and 2-propanol, a new feature that grows steadily from temperatures lower than about 250 K in solvents that are hydrogen-bond donors.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1999
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Study of the ground state and low-lying excited states involved
Article Abstract:
The influence of internal coordinate changes on photophysical mechanisms involved in the photogeneration of charge carriers in composites formed by organic semiconductors was investigated using quantum chemistry methods. A model composite produced from poly(p-phenylenevinylene) as the principal component and perylene as the minor component was analyzed for this purpose. In addition, the ground state and several low-lying excited states including charge-transfer and local excited states were evaluated.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1998
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Third-order nonlinear optical properties in the excited state of well-defined thiophene-dimethylsilyl co-oligomers
Article Abstract:
A novel class of oligomers for nonlinear optics, the thiophene-dimethylsilyl co-oligomers (TSi)(sub n)-T where n = 1-3, was synthesized. The objective was to combine third-order nonlinear optical response and transparency in the visible region. To this end, fluorescence spectra, stationary-state absorption spectra and time-resolved absorption were performed. Experimental results showed that the absorption spectra of (TSi)(sub n)-T are not red-shifted as n increases in contrast with oligothiophenes.
Publication Name: Journal of Physical Chemistry B
Subject: Chemicals, plastics and rubber industries
ISSN: 1520-6106
Year: 1998
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