Showing papers on "Pentacene published in 1990"
TL;DR: In this article, the authors used a combination of laser frequency-modulation absorption spectroscopy and either Stark, longitudinal ultrasonic, or transverse ultrasonic internal modulation to detect persistent spectral holes in the pentacene/p-terphenyl system.
Abstract: With the use of a combination of laser frequency-modulation absorption spectroscopy and either Stark, longitudinal ultrasonic, or transverse ultrasonic internal modulation, the optical absorption spectrum of a single impurity molecule of pentacene in a p-terphenyl crystal may be measured at liquid helium temperatures. The general properties of this detection method are illustrated by first applying the technique to the detection of persistent spectral holes in the pentacene/p-terphenyl system. Selection of a single absorber for measurement is accomplished by tuning the probing laser far out into the wings of the inhomogeneously broadened O-O absorption lines for either the O{sub 1} or O{sub 2} sites. The single-molecule line shape is similar to that predicted by a simple model of the double-modulation process. The approximate amplitude of the single-molecule signals suggests that triplet bottleneck power broadening is suppressed far out in the wings of the inhomogeneous line. This work probes the ultimate N = 1 limit of the statistical fine structure present in all inhomogeneous absorption lines.
83 citations
TL;DR: Using highly efficient Fluorescence excitation spectroscopy of individual pentacene molecular impurities in p-terphenyl crystals, it is observed that some pentacenes defects exhibit spontaneous spectral jumps in their resonance frequency at 1.5 K, with a jump rate independent of laser power.
Abstract: : Using highly efficient Fluorescence excitation spectroscopy of individual pentacene molecular impurities in p-terphenyl crystals, we have observed that some pentacene defects exhibit spontaneous spectral jumps in their resonance frequency at 1.5 K, with a jump rate independent of laser power. In addition, the low-power limiting linewidth for single pentacene absorbers reaches the lifetime limit of 7.8 MHz at 1.5 K.
46 citations
TL;DR: In this article, a coherent, fully resonant four-wave mixing (FRFWM) spectroscopy was used to probe the vibrational and vibronic state of the pentacene S0 and S1 electronic states.
Abstract: Coherent, fully resonant four‐wave mixing (FRFWM) spectroscopy is used to probe the vibrational and vibronic state of the pentacene S0 and S1 electronic states. High resolution is obtained using mixed molecular crystals at cryogenic temperatures. The FRFWM spectra combined with conventional absorption and fluorescence spectra allow correlation of the S1 fundamentals to the corresponding ground state normal coordinates. Couplings between modes are indicated and may be related to Fermi resonance of the pentacene vibrations by means of host librational phonons.
27 citations
TL;DR: In this article, it was shown that the IR emission spectrum in objects as the Orion ridge is compatible with the presence of two-to five-ring linear PAH species in amorphous carbons (specifically, the derivatives of naphthalene, anthracene, tetracene and perhaps pentacene).
Abstract: It is shown that the IR emission spectrum in objects as the Orion ridge is compatible with the presence of two- to five-ring linear PAH species in amorphous carbons (specifically, the derivatives of naphthalene, anthracene, tetracene, and perhaps pentacene). An origin for these molecules in carbon dust is indicated and is consistent with the structure of laboratory hydrogenated amorphous carbons. Benzene and the simplest aromatic ring molecule, cyclopropenylidene, may be observable in sources which show the UIR emission features. 25 refs.
24 citations
TL;DR: In this paper, a coherent, fully resonant four-wave mixing (FRFWM) spectroscopy was used to probe the vibrational and vibronic state of the pentacene S0 and S1 electronic states.
Abstract: Coherent, fully resonant four‐wave mixing (FRFWM) spectroscopy is used to probe the vibrational and vibronic state of the pentacene S0 and S1 electronic states. High resolution is obtained using mixed molecular crystals at cryogenic temperatures. The FRFWM spectra combined with conventional absorption and fluorescence spectra allow correlation of the S1 fundamentals to the corresponding ground state normal coordinates. Couplings between modes are indicated and may be related to Fermi resonance of the pentacene vibrations by means of host librational phonons.
01 Jan 1990
TL;DR: The intercalation of TaS2 and TiS2 with large aromatic organic guests is presented in this article, where large, neutral aromatic compounds, such as pentacene and tetracene, are introduced into these metal dichalcogenides, in the hope of observing novel structural and physical characteristics.
Abstract: The intercalation of TaS2 and TiS2 with large aromatic organic guests is presented here. Recently, it has been reported that sonication of the sodium intercalate of these materials allows for a rapid intercalation of many large molecules [1]. Therefore, we attempted to introduce large, neutral aromatic compounds, such as pentacene and tetracene, into these metal dichalcogenides, in the hope of observing novel structural and physical characteristics.