RAMAN ANALYSIS OF CHEMICAL-REACTIONS RESULTING FROM THE COLLISION OF MICROMETER-SIZED PARTICLES

The chemical reaction between two micrometer-sized particles has been studied with the use of Raman spectroscopy. Charged particles of Na2CO 3 and (NH4)(2)SO4 were generated with the use of a vibrating orifice a erosol generator fitted with an inductive charging plate. Two particle s, one of each substance and of opposite polarity, were held apart by the de electric field of an electrodynamic balance (EDB) and then brou ght together by manipulating the de potential to permit Coloumbic forc es to dominate. Raman spectra taken of the particle aggregate show tha t chemical reaction did not occur when dry particles were combined, bu t subsequent exposure of the aggregate to water vapor induced a chemic al reaction that resulted in the formation of Na2SO4. The Raman data a re presented, and the reaction mechanism and products are discussed.