Detection and Spectroscopy of Single Pentacene Molecules in a p- Terphenyl Crystal by Means of Fluorescence Excitation
Abstract
Recent advances in fluorescence excitation spectroscopy with high efficiency have produced greatly improved optical spectra for the first electronic transition of individual single molecules of pentacene in p-terphenyl crystals at low temperatures (1.5 to 10 K). Two classes of single molecules behavior are observed: class I molecules have time independent resonance frequencies, and class II molecules show a diffusive motion among several resonant frequencies with time which we term spectral diffusion by analogy with a similar effect which is common in amorphous materials. The temperature dependence of the linewidth and power dependence of the fluorescence emission rate and of the linewidth are reported and analyzed. Various forms of the surprising class II behaviour are described, including jumping among several discrete frequencies, creeping toward the center of the inhomogeneous line in many small steps, and a wandering among many possible resonance frequencies. The occurrence of class II behavior is restricted to the wings of the inhomogeneous line suggesting that the effect is correlated with some form of local disorder.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 22, 1991
- Accession Number
- ADA243747
Entities
People
- T. Basche
- W. E. Moerner
- W. P. Ambrose
Organizations
- International Business Machines Corporation (Armonk, NY)