Laser induced changes in Pt and Tl metal nanoparticles

Effect of laser pulse irradiation on platinum and thallium metal nanoparticles was studied. Laser pulse excitation of d-electrons in Pt nanoparticles leads to the trapping of electrons at the interface without much change in the steady-state absorption spectrum. TEM results show that the particles undergo a shape transformation and fragmentation on laser pulse irradiation. Studies carried out on Tl particles after laser pulse excitation shows an initial blue shift in the absorption band indicating decrease in the particle size. However, longer irradiation leads to dissolution of the particles. The results are discussed on the basis of energy transfer from the electrons to the surface atoms.