OPTICAL SPECTROSCOPIC STUDY OF THE DOMAIN-STRUCTURE OF TRICLINIC P-TERPHENYL

The relative intensities, at 4.2 K, of fluorescence lines attributed t o tetracene guests in different sites of a p-terphenyl host crystal ar e shown to depend on the rate of cooling of the crystal between 240 an d 140 K across the disorder-order phase transition. This observation r eflects the kinetics of the formation of the domain structure in the l ow-temperature phase, which affects the distribution of guest molecule s located within domains and within domains boundaries.