|MadSci Network: Chemistry|
Michael, The plasma of an Inductively Coupled Plasma (ICP) is comprised of a significant concentration of both Argon cations (Ar+) and electrons such that the net charge in the plasma is zero. Once the plasma ionization is initiated (usually from a spark from a Tesla coil), the radio frequency generator provides the energy to maintain the ionization. The argon plasma can reach temperatures of more than 10,000 K but the heat produced is not the result of combustion or chemical reaction. Instead, the high powered radio frequency supplies energy to the ions and electrons within the coil. Argon atoms are normally deemed as inert which means that they are very stable in their uncharged state. In order to keep the cations and electrons apart, the Rf generator is tuned to a frequency which the plasma can absorb and will keep the atoms ionized. The absorbed Rf energy is converted by the plasma and in turn released as heat. Using this principle the temperature of the plasma can be varied by increasing or decreasing the power of the radio frequency. As a result, the optimum plasma temperature can be used depending on the type of analysis being carried out. Upon exiting the radio frequency coil, the ions and electrons no longer have the energy from the coil to remain separate and recombine into argon atoms. I hope this answers your question. John.
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