In the last decades, laser processing has become an important route for producing nano- and submicrometer particles. Pulsed laser ablation method uses a focusing laser beam which can bring high energy density on small areas on target which leads to explosive particles formation [1]. Using an unfocused laser beam for irradiation of nanoparticles dispersed in liquid results in a completely different formation of particles. These irradiated particles are melted and merged to form submicrometer spherical particles [2-3].

    In this work we investigate experimentally and theoretically the physical and chemical processes involved in particles formation by laser irradiation of α-Fe2O3 raw nanoparticles dispersed in different organic solvents. Fig. 1(a) and (b) shows an exemplary SEM image of obtained composite particles and XRD results for three different solvents, respectively. In our research we focus on the role of solvent, interaction between irradiated particles and also interactions between particles and solvent molecules. Besides this we will show details on the influence of temperature and initial size of raw nanoparticles on the submicrometer particle formation process. We believe that exploring the interactions between irradiated material and solvent molecules and investigating the thermodynamic behavior of particles in various circumstances are necessary to design and produce materials with specific unique structures and desired physical properties.