Emission dynamics from doped crystals of (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CH</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">NMnCl</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>(TMMC): Exciton trapping in a one-dimensional lattice

The emission decay curves from (${\mathrm{CH}}_{3}$${)}_{4}$${\mathrm{NMnCl}}_{3}$ [tetramethylammonium manganese chloride (TMMC)] crystals doped with small amounts of ${\mathrm{Cu}}^{2+}$ deviate dramatically from simple exponential form. Consistent with the linear chain structure of TMMC, the curves are adequately described by decay expressions derived for exciton trapping in one-dimensional systems. Analysis of the data indicates that exciton migration in TMMC is nearly one-dimensional with an intrachain hopping frequency at room temperature of ${10}^{11}$ to ${10}^{12}$ ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$ and an interchain hopping frequency of only ${10}^{2}$ to ${10}^{4}$ ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$. The presence of small concentrations of ${\mathrm{Cd}}^{2+}$, a scattering impurity, greatly reduces the rate of exciton trapping. The temperature dependence of the decay curves suggests an energy barrier of 800 to 1000 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ for migration along the chains in TMMC.

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