Molecular Dynamics-Based Approach for Laser-Induced Cavitation Bubbles: Bridging Experimental and Hybrid Analytical–Computational Approaches

Cavitation phenomena and their importance drive research efforts to characterize their behavior through experimental, analytical, and computational approaches. However, experimental approaches struggle to capture molecular-level details; analytical methods are often limited in application and accuracy; and computational techniques may miss key physical phenomena such as phase transitions. To address these limitations, the current study introduces laser-based molecular dynamics (MD) based on a coarse-grained (CG) model as a promising approach to investigate the dynamics of cavitation bubbles at the molecular-level, covering nucleation, growth, collapse, evaporation, phase transition, liquid–vapor interphase, and subsequent regrowth/collapse cycles. The research was performed with an experimental study on millimeter-scale bubble cavitation under ambient and free conditions. The obtained observations were used to model the laser–liquid interaction. This analytical model was then implemented in an MD method to investigate the dynamics of the nanobubbles. The simulations revealed that directing a 1 fJ laser pulse at water generates a hot plasma, which expands spherically through collision cascades and generates a nanobubble. The nanobubble grows to a maximum radius of 5.26 nm and collapses within 17 ps, followed by subsequent regrowth/collapse cycles. At maximum radius, the vapor–liquid interphase exhibits a thickness of 0.8 nm with a density range of 0.105 to 0.840 g/cm³. Cold evaporation temperatures ranging from 300 to 315 K and vapor density of 4.5_–1.5^+1.5 × 10^–5 g/cm³ were captured inside the nanobubble. These results, which align with experimental data, confirm the effectiveness of the proposed MD-based algorithm in investigating laser-induced cavitation nanobubbles. Moreover, this algorithm can be extended to investigate radical species of water or chemical reactions under laser radiation and cavitation in all-atom model simulations.