Mechanism of inactivation of plankton microorganisms by acoustic shock waves is discussed. Shock waves occur at very rapid formation and collapse of vapor bubbles in a liquid locally point heated to a temperature exceeding the boiling. Local heating was provided by pulsed laser excitation of organic photothermal sensitizers. An effective photothermal sensitizer should have a very short lifetime (picoseconds) of excited states. High excited electronic states (HEES) of organic dyes follow this requirement. HEES are produced as a result the stepwise absorption of two photons by the molecule through the lower excited states. The formation and disappearance of vapor bubbles in the solution was detected as a change in the light scattering of a low-intensity helium-neon laser beam passing through the cuvette.
high excited electronic states of molecules, local heating, shock waves, inactivation of microorganisms
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