Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.283, 185-190, 1996
Pressure Effects on Single Molecules of Terrylene in P-Terphenyl
Fluorescence excitation spectra of single molecules and persistent holes of terrylene in p-terphenyl crystals were investigated under hydrostatic pressure up to 10510 hPa. Single-molecule lines could be observed around all four inhomogeneous bands X(1) to X(4). They showed a linear and reversible pressure shift between -0.92 MHz/hPa and -1.55 MHz/hPa with no clear differences between the inhomogeneous bands. The relative fluctuations of the pressure shift parameter between different molecules are larger than for pentacene in p-terphenyl which indicates a less well-ordered local environment of the dopant molecules. Persistent hole-burning was possible in the bands X(1) and X(3) of the same samples in which single-molecule lines were observed. The pressure shift of the hole spectra (which are close to the band center) is smaller than the shift of the single-molecule lines (in the wings of the band). lit Hence, the molecules seem to feel different local compressibilities.
Keywords:SPECTROSCOPY;PENTACENE