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Probe Spectroscopy (probe + spectroscopy)

Distribution by Scientific Domains

Chemistry	80%

Selected Abstracts

Remarkable Site Difference of Vibrational Energy Relaxation in Benzene Dimer: Picosecond Time-Resolved IR,UV Pump,Probe Spectroscopy,

ANGEWANDTE CHEMIE, Issue 39 2010
Ryoji Kusaka
Ganz entspannt: Die Schwingungsenergierelaxation (VER) von Isotopologen des Benzol-Dimers auf dem C-H-Streckschwingungsniveau wurde durch zeitaufgelöste Pikosekunden-IR-UV-Pump-Sonden-Spektroskopie untersucht (siehe Bild, h=C6H6, d=C6D6). Dabei ergab sich ein bemerkenswerter Unterschied in den Relaxationslebensdauern: Die Lebenszeit des ,stehenden" Benzolmoleküls (,Stem", 110,ps) ist 4.5mal kürzer als die des ,liegenden" (,Top", 500,ps). [source]

Observation of Terahertz Vibrations in the Nitrogenase FeMo Cofactor by Femtosecond Pump,Probe Spectroscopy,

ANGEWANDTE CHEMIE, Issue 23 2010
Ines Delfino Dr.
Hochgepumpt: Die Dynamik des durch Resonanz-Raman-Spektroskopie nicht charakterisierbaren FeMo-Cofaktors (siehe Bild) wurde nun mit kohärenter Puls-Schwingungsspektroskopie als Sonde untersucht: Ein Laserpuls mit sichtbarem Licht (15,fs) pumpte die Probe in einen angeregten elektronischen Zustand, und ein zweiter Puls (<10,fs) untersuchte die Änderung in der Transmission als Funktion des Zeitabstands. [source]

Energy-dispersive absorption spectroscopy for hard-X-ray micro-XAS applications

JOURNAL OF SYNCHROTRON RADIATION, Issue 5 2006
S. Pascarelli
Originally developed for time-resolved X-ray absorption spectroscopy (XAS), energy-dispersive absorption spectroscopy offers new opportunities for applications such as fluorescence detection and microbeams for scanning probe spectroscopy, thanks to recent developments in both instrumentation and optics. In this context, this paper presents a first example of chemical mapping recorded at ID24, the energy-dispersive XAS beamline at the ESRF. Attributes of this geometry for microanalysis are addressed. Finally, present and future plans are discussed and developed in the light of the evolution of the focal spot on this instrument in the past ten years. [source]

Optically pumped lasing and gain formation properties in blue Inx Ga1,x N MQWs

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 12 2004
K. Kojima
Abstract Lasing and gain formation properties have been studied in an InxGaN1,x multiple quantum wells lasing at around 460 nm by employing the modified variable stripe length method (VSLM) and pump and probe spectroscopy (P&P). It was found that the spontaneous emission (Esp) appeared far below absorption edge (Ea) that is observed as a photo-bleaching negative-peak in P&P, indicating the formation of localized tail states. Lasing peaks appeared in between Esp and Ea with wide spectral distribution. This is consistent with the results where VSLM revealed the broad feature of optical gain spectra associated with rapid peak saturation of lasing even just above the threshold photo-pumping power density. Such mechanism observed in In-rich InxGa1,xN MQWs is contributed not only from the broad distribution of localized density-of-states but also from hot carrier distribution (determined by Maxwell,Boltzmann statistics), temperature of which is raised up due to long energy relaxation time to localized tail states. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Energy Transfer in Single Hydrogen-Bonded Water Molecules

CHEMPHYSCHEM, Issue 6 2005
Huib J. Bakker Prof.
Abstract We study the structure and dynamics of hydrogen-bonded complexes of H2O/HDO and acetone dissolved in carbon tetrachloride by probing the response of the OH stretching vibrations with linear mid-infrared spectroscopy and femtosecond mid-infrared pump,probe spectroscopy. We find that the hydrogen bonds in these complexes break and reform with a characteristic time scale of ,1 ps. These hydrogen-bond dynamics are observed to play an important role in the equilibration of vibrational energy over the two OH groups of the H2O molecule. For both H2O and HDO, the OH stretching vibrational excitation relaxes with a time constant of 6.3±0.3 ps, and the molecular reorientation has a time constant of 6±1 ps. [source]