Abstract
Acoustic cavitation in liquids submitted to power ultrasound creates transient extreme conditions inside the collapsing bubbles which are the origin of unusual chemical reactivity and light emission, known as sonoluminescence. In the presence of noble gases, a nonequilibrium plasma is formed inside the collapsing bubbles. Chemically active species formed inside the bubbles are able to diffuse into the liquid phase and react with solution precursors to form a variety of products. Many studies reveal the advantages of ultrasound to activate the divided solids and extended solid surfaces. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects.