High-pressure dielectric spectroscopy

Kinetic studies of free-radical initiation in CO2 were conducted using AIBN as the initiator [16, 29]. The study was undertaken using high-pressure UV spectroscopy. The results showed decomposition to be slower in CO2 relative to that measured in benzene owing to the reduced dielectric strength of carbon dioxide. However, it was also determined that the initiator efficiency is much higher in CO2 because of reduced viscosity and solvent cage effects. Initiator... 

The attenuation of ultrasound (acoustic spectroscopy) or high frequency electrical current (dielectric spectroscopy) as it passes through a suspension is different for weU-dispersed individual particles than for floes of those particles because the floes adsorb energy by breakup and reformation as pressure or electrical waves josde them. The degree of attenuation varies with frequency in a manner related to floe breakup and reformation rate constants, which depend on the strength of the interparticle attraction, size, and density (inertia) of the particles, and viscosity of the Hquid. 

Many other types of atomization devices have been used in atomic spectroscopy. Gas discharges operated at reduced pressure have been investigated as sources of atomic emission and as ion sources for mass spectrometry. The glow discharge is generated between two planar electrodes in a cylindrical glass tube filled with gas to a pressure of a few torr. High-powered lasers have been employed to ablate samples and to cause laser-induced breakdown. In the latter technique, dielectric breakdown of a gas occurs at the laser focal point. 

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