Publication Date:
2016-02-27
Description:
Low temperature (20–230 K) spectral-luminescence studies were conducted on C 60 fullerite saturated with carbon monoxide in a physisorption regime. Substantial changes in the photoluminescence characteristics of C 60 –CO solutions with different impurity concentrations were found already for short intercalation times. Strong dependence of the CO solubility on the saturation temperature was revealed by analyzing the contribution of “deep X-traps” to the luminescence. Furthermore, it was found that filling of the octahedral voids by CO molecules occurs with a lower gradient of the impurity distribution into the bulk C 60 crystals as compared with N 2 . The temperature dependences of the integral emission intensity for the samples with different concentrations of carbon monoxide were studied. For the first time, using the spectral-luminescence method, it was revealed that CO molecules, in contrast to H 2 and N 2 , exhibit a significant effect on the formation of the orientational glass and the rotational dynamics of C 60 molecules. Within the model of the transfer of electronic excitation in C 60 crystals, the effect of polar CO molecules on the reorientation of C 60 molecules and the change in the nature of their rotation in concentrated C 60 –CO solutions, leading to the observed strong shift of the temperatures of orientational T c and glass T g transitions to lower temperatures accompanied by “blurring” of the transition boundaries, were explained.
Print ISSN:
1063-777X
Electronic ISSN:
1090-6517
Topics:
Physics
