Abstract
Nonexponential photon-echo decay curves and non-Lorentzian persistent-hole shapes of chromophores in organic glasses have been observed experimentally, and explained by considering fractal structures of the organic-glass hosts. The photon-echo decay curves are well reproduced by the nonexponentially decaying function of \ensuremath{\tau}, exp(-cT${\mathrm{\ensuremath{\tau}}}^{\mathit{D}/3}$), where c is a constant, T is the temperature, \ensuremath{\tau} is the delay time between the first and second excitation pulses, and D is the fractal dimension of the glass host. The persistent-hole shapes are also well reproduced by the Fourier transform of this function. The fractal dimensions D obtained by fitting the theoretical curves to the observed hole shapes were characteristic of the hosts, and almost independent of the guest chromophore. The non-Lorentzian persistent-hole shapes were observed in nonionic as well as in ionic guest chromophores. We also obtained consistent values of the host fractal dimension from the photon-echo decay curves. A simple model of glass structure is presented which can consistently explain the differences between polymeric glass host and monomeric glass host with regard to the measured hole shapes, echo decay curves, and the interrelations between the hole widths and the inhomogeneous widths.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call