Index of content:
Volume 34, Issue 6, June 2008
- LOW-DIMENSIONAL AND DISORDERED SYSTEMS
34(2008); http://dx.doi.org/10.1063/1.2920177View Description Hide Description
Spectroscopic studies of vitreous 2-bromobenzophenone have been carried out over the respective domain of its stability. Glassy 2-bromobenzophenone samples were obtained by abrupt cooling of the melt by cold helium vapor. Quantum yield measurements allowed us to establish that the upper boundary of stable glass is slightly above , while at about the glass melts. Phosphorescencemeasurements at showed that even at this low temperature the emission contains a strong excimer component. The energy position and shape (two bands) of the excimer emission are close to those observed in the crystal of 2-bromobenzophenone at higher temperatures. Contrary to findings in the crystal, the monomeric emission of the glass contains only one stretch series, every band of which is substantially broader than in the crystal. As the temperature is raised, the monomeric emission intensity falls, disappearing completely above .
The effect of the noncentral impurity–matrix interaction upon the thermal expansion and polyamorphism of solid solutions at low temperatures34(2008); http://dx.doi.org/10.1063/1.2920178View Description Hide Description
Orientational glasses with molecules occupying 26 and 90% of the octahedral interstitial sites in the lattice have been investigated by the dilatometric method in a temperature interval of . At temperatures of the glasses undergo a first-order phase transition which is evident from the hysteresis of the thermal expansion and the maxima in the temperature dependences of the linear thermal expansion coefficients and the thermalization times of the samples. The effect of the noncentral interaction upon the thermal expansion and the phase transition in these glasses was clarified by comparing the behavior of the properties of the and solutions.