Investigating the Nanoparticle Transition from Bulk Behavior to Discrete Atom/Finite Size Behavior Using Laser Induced Pressure Generation
Detailed investigations have been carried out [1,2] on the response of microparticles and nanoparticles to lasers of various pulse durations and energies. A first principles model has been developed that allows the prediction of all thermo-mechanical effects that will be generated from any laser pulse, such as pressure generation and phase changes. This theoretical work also predicts the thermo-mechanical effects transmitted to the surrounding transparent medium that the nanoparticles are immersed in, such as water or a solid polymer. The use of short enough pulses produces shock fronts in the surrounding medium. We calculate how short the laser pulse must be as a function of nanoparticles properties. We also show that measurements of pressure peaks in the medium can be used to determine the thermo-mechanical properties of the absorbing nanoparticles, such as bulk modulus and thermal expansion coefficient. Because the measurements can be made in the surrounding medium, they are easier to perform experimentally. Using this approach on particles of decreasing size, measurements of the pressure in the medium allow the determination of the size at which a nanoparticle is small enough to deviate from its bulk behavior and manifest discrete atom, finite size effects. This allows the prediction of how the thermo-mechanical properties of nanoparticles will change as their size decreases.
Chunli BAI, Sishen XIE, Xing ZHU
B. S. Gerstman "Investigating the Nanoparticle Transition from Bulk Behavior to Discrete Atom/Finite Size Behavior Using Laser Induced Pressure Generation", Solid State Phenomena, Vols. 121-123, pp. 1025-1028, 2007