Objetivo
The main goal of the present project is to investigate and develop modern experimental techniques based on high resolution time domain pico- and femto- second polarisation spectroscopy (PS) and laser induced fluorescence (LIF), for probing molecular collisions and orientation relaxation of small molecules in the gas phase. Emphasis will be put on the investigation of environments, which are realistic for conditions encountered in practical laser diagnostic situations. Examples are temperature measurements in combustive and non-combustive flows, reacting plasma environments and kinetic flow reactors. Measurements in practically important collisional environments for the investigation of the influence of buffer gas species on the polarisation signal intensity will be accompanied by theoretical studies on the efficiency of collisions on quenching and rotational energy redistribution. A novel two photon PS technique (TIPS) will also be developed which will allow access to many small molecular species whose accessible transitions are located in the vacuum-ultraviolet spectral region. The corresponding theoretical description of the process will be created for a quantitative interpretation of PS signals at various pressures and as a function of laser intensity and beam polarization geometry.
Three experimental and two theoretical groups will collaborate on this project:
The first INTAS group. Team leader Dr Thomas Dreier, co-ordinator of the project, Heidelberg, Germany.
Experimental investigation: PS of 1-photon transitions of the characteristic vibration-rotation spectrum of ethylene and methanol using CO2-laser radiation, of NO2 in the visible spectral range, and time resolved PS of several diatomic species (OH, NH, NO) in flames using tunable ps-laser systems.
The second INTAS group. Team leader Dr Clemens Kaminski, Lund, Sweden.
Experimental investigation: Two-photon PS of atomic and molecular species in optically accessible cells at low to moderate pressures.
The first Belarussian group. Team leader Professor Alexander Blokhin, Minsk, Belarus.
Theoretical investigation: Improving the treatment of molecular collisions and orientation relaxation for the interpretation of the polarisation measurements provided by the experimental groups within the collaboration. Construction of a uniform theoretical approach, which allows one to extract information about peculiarities of molecular rotation in collisional environments from time-resolved and spectral PS and LIF measurements.
Experimental investigation: femto- and picosecond studies of the transient photoanisotropy of combustion relevant molecules in the gas phase.
The second Belarussian group. Team leader Professor Igor Gancheryonok, Minsk, Belarus.
Theoretical investigation: clarification of polarisation-geometry dependent peculiarities in PS (including polarisation statistics and polarisation inhomogeneity effects), developing "the strong field theory" of PS without restrictions on the pump beam intensity, creation of theoretical descriptions for a recently developed polarisation-modulated spectroscopy technique based on a vector two-wave mixing interaction.
The NIS group. Team leader Dr Andrei Sharkov, Moscow, Russia.
Experimental investigation: Studies of several diatomic molecules and radicals in the gas phase using femtosecond time resolved PS schemes.
Tema(s)
Convocatoria de propuestas
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69120 Heidelberg
Alemania