TEMPERATURE BROADENING OF IMPURITY TRANSITIONS IN THE CRYSTALLINE ANDGLASSY PHASE OF BENZOPHENONE

The temperature dependence of the width of spectral holes in the cryst alline and glassy phase of benzophenone: chlorin solid solutions is me asured between 1.5 and 10 K. In the crystal, the holewidth levels on G AMMA(0) = 45 MHz for T < 5 K. This is close to the lifetime-limited va lue. For T > 5 K, it exhibits a rapid increase. In the glassy phase, t he holewidth exceeds that in the crystalline state by more than a fact or of ten. For T < 4 K, the width is governed by a power law with an e xponent of 1.28. Around 5 K, there is a clear onset of a much steeper dependence.