Self-trapped polaron exciton in neutral fullerene<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mrow><mml:mn>60</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

The luminescence of ${\mathrm{C}}_{60}$ was investigated as a function of temperature between 300 and 10 K and for various oxygen concentrations. Its intensity was found to increase strongly with decreasing temperature down to about ${\mathit{T}}_{1}$=100 K and to decrease again for a further reduction of T. Below 100 K, new structures appeared in the spectra. The experiments are described by a self-localized polaron exciton and by a diffusing free exciton above and below ${\mathit{T}}_{1}$, respectively. The important difference between the two regions is the free rotation of the ${\mathrm{C}}_{60}$ above and the definite orientation below ${\mathit{T}}_{1}$.

Hali tarjima qilinmagan