Obiettivo Four novel areas of application of supercritical fluid technology to laser techniques in analytical, mechanistic and materials chemistry will be investigated. Firstly, the development of capillary cells for Raman and time-resolved infrared spectroscopy at high pressures. Time-resolved infrared (TRIR) spectroscopy is becoming an increasingly important technique for investigating mechanistic pathways in organometallic chemistry and, more recently, in organic reactions. The high pressures involved in such experiments impose severe constraints on the equipment. However, very versatile but inexpensive cells have recently been developed using high pressure capillary tubing and IR optic fibres. The cells have been proved to work satisfactorily but a sustained programme is now required to exploit these cells and to establish precisely how reaction rates in supercritical fluids compare with those in conventional solvents. Secondly, photoacoustic measurements in supercritical and conventional solvents. Photoacoustic calorimetry (PAC) has been used to estimate the enthalpy of interaction of coordinatively unsaturated organometallic reaction intermediates with hydrocarbon solvents. Supercritical fluids offer a considerable variety of unusual aprotic reaction media. Experiments have been begun to make PAC measurements in supercritical fluids. Supercritical PAC will provide enthalpy data, analogous to the information about solvent interactions from conventional PAC. This probe will also provide a new route to the data needed for understanding and manipulating these fluids as reaction media. Thirdly, laser deposition of thin films using precursors dissolved in supercritical fluids. The laser deposition of thin films of conducting and semi-conducting films from organometallic precursors in the gas phase is of principal interest in the current research. These techniques are severely limited by the availability of suitably volatile organometallic compounds. Finally, laser ablation/mass spectrometry for analysis of heavy organic in polymers. A laser ablation/mass spectrometry technique which uses a wide range of lasers (CO2, NdYAG, XeCl, KrF, etc.) for ablation of the surface and a similar selection of laser for ionisation of the resulting vapour for analysis by time of flight mass spectrometry has been developed. The ability to choose the most appropriate laser for ablation of a particular material gives increased sensitivity and selectivity and "soft ionisation" techniques make it possible to detect large molecules without fragmentation. One of the limitations of the technique is that the material must absorb light from the ablating laser and many important materials such as polyethylene are totally transparent to most easily accessible laser sources. The use of supercritical fluids for impregnating polymers, to overcome this limitation, will be exploited. In this way, highly absorbing compounds can be introduced into otherwise transparent polymers so that laser ablation can be used for analysis. Programma(i) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Argomento(i) 15 - Condensed Matter Physics Invito a presentare proposte Data not available Meccanismo di finanziamento Data not available Coordinatore UNIVERSITY OF NOTTINGHAM Contributo UE Nessun dato Indirizzo University Park NOTTINGHAM Regno Unito Mostra sulla mappa Collegamenti Sito web Opens in new window Costo totale Nessun dato Partecipanti (1) Classifica in ordine alfabetico Classifica per Contributo UE Espandi tutto Riduci tutto Scientific Research Centre for Technological Lasers Russia Contributo UE Nessun dato Indirizzo 142092 Troitsk, Moscow Region Mostra sulla mappa Costo totale Nessun dato
