Species with sizes less than the diffraction limit cannot be visualized in liquids by direct optical methods. We are developing new experimental methods for determining positions and sizes of individual plasmonic nanoparticles in the liquid phase by rapid laser heating. The heat conduction within the multiphase system (particle-gas-liquid) results in the production of gaseous bubbles around the particles, which can be used to estimate their positions as well as their sizes by thermodynamic modeling. Another application of the work is to develop more accurate models for estimating heat delivery by the particles, which is important for heat solar heat capture applications and photothermal cancer treatment. Our current work extends the previously developed techniques to visualize ionic species in aqueous solutions together with the implementation of classical density functional theory methods for describing the dynamic response of the system.