LUMINESCENCE FROM C-60 SINGLE-CRYSTALS IN GLASSY PHASE UNDER SITE-SELECTIVE EXCITATION

Luminescence from C-60 single crystals has been investigated at liquid He temperature under selective excitation into the tail part below th e fundamental absorption edge. Luminescence line narrowing is observed for resonant excitation, in which a characteristic vibrational quantu m is found similar to 420 cm(-1) in the excited state. It is revealed that the spectrum which has been known as photo-luminescence from C-60 single crystals is an superposition of site-selective luminescence fr om several localized states. Such inhomogeneity is most likely to aris e from fluctuation of the intermolecular orientational correlation in a pair of C-60 molecules over which the excitation is delocalized. (C) 1998 Elsevier Science B.V. All rights reserved.