Low temperature tunneling of triplet excitation energy

Optical detection of spin coherence in a defect center of a molecular crystal

“…Op디C려 detection of SE has been performed on isolated centers [7,12,13,[16][17][18] and excitons in molecular cryst머s [18]. In this kind of experiment three πl2 -pulses are followed by a .7rI2-pulse necessary for optic떠 detection.…”

“…Two-(or three-)exponential decays have been observed so far for all SE experiments in molecular cryst떠s [7,12,13,[16][17][18]. In isolated molecular centers the short component 자 is in the order of 자 > 100 μs， whereas for the tetrachlobenzene exciton it is 자 르 2 μs [18].…”

“…We have 외ready applied some of the p띠se sequences to chemically mixed cryst외s [5][6][7] in order to get information about the extension and structure of induced defects in organic molecular crystals. These defects are induced by doping a molecular crystal with as compared to the host chemically different molecules.…”

Triplet States and Triplet Excitons in Chemically Mixed Crystals of Acridine with Anthracene

“…On top of that, it has turned out in the course of experiments that even in such thermodynamically favourable cases like solid solution of anthracene and acridine where the host lattice can contain as much as tens of mol% of the guest [3,4], the analysis of experimental results may become very obscure (if not impossible at all) due to the fact that energy levels of host and guest and of different resonance aggregates are overlapping even at moderate guest concentrations, and both, the variety of aggregates and the overlap are strongly increasing with increasing guest concentration [5][6][7]. And although all these drawbacks and limitations have resulted in the shift of a centre of gravity of the research effort to isotopically mixed crystals, systematic studies of chemically mixed crystals (lightly and highly concentrated with the guest molecules) have provided some interesting results and concepts relevant to the exciton transport and trapping [8][9][10][11], formation of excited complexes and aggregation properties [12,13] or aggregation-controlled molecular photophysics [7].…”