ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
This paper presents real values of photochemical hole-burning (PHB) parameters for dye-doped polymer systems. The cross section for purely electronic zero-phonon absorption σ*0, quantum efficiency of hole formation η and full-width at half-maximum of inhomogeneous broadening Δωi are determined by the least-squares fitting method. Our sample is sulfonated tetraphenylporphin doped in polyvinyl alcohol at 20 K. The determined values are σ*0 = (2.3 ± 0.2)× 10−15 cm2, η=(1.6±0.6)×10−2, and Δωi=(223±7) cm−1. The errors are of the order of a standard deviation. The η is much greater than previously reported values. The apparent quantum efficiencies of hole formation are derived under the assumption that the lowest-energy absorption band consists of transitions of one type. They exhibit a marked wavelength dependence, but their values are well explained quantitatively by the real values. There is no need to consider any wavelength dependence of σ*0 and η, at least at the initial stage of burning. The purely electronic transition component is about half of the lowest-energy absorption band. The other component is ascribed to at least two kinds of vibronic transitions of the dye. The Debye–Waller factors for these two vibronic transitions are roughly estimated to be in the order of 10−2. This result means the site-selectivity in PHB is not perfect in a wide range of the lowest-energy absorption band.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.465869
