Potential Energy as Descriptor for Nanoparticle Coalescence

Coalescence is a fundamental process in gas-phase synthesis of nanoparticles (NPs), affecting their structure and resultant properties. Various metrics are currently used to measure the degree of coalescence in atomistic simulation studies, such as the radius of the neck formed between the NPs’ centers of mass, gyration radii, sphericity, and surface area changes. A common characteristic of such metrics is that they typically require additional, often painstaking, data manipulation. Here, a new descriptor is introduced, the Overall Reduced Change in Potential Energy (ORCiPE) between initially uncoalesced and coalesced configurations. To benchmark the descriptor, its definition is analogous to that of the Overall Change in Surface Area, a common and dependable metric. When no phase transition occurred, comparison with other metrics confirms the reliability of ORCiPE in coalescing Au NPs. Considering that potential energy is a standard output property in atomistic simulations, ORCiPE is proposed as a valuable and facile coalescence metric.