Coalescence of two nanoscopic argon droplets by molecular dynamics simulation

Coalescence of argon droplets with a radius of R=25, 50 and 100 nm was studied with molecular dynamics simulation. The truncated and shifted Lennard-Jones (LJTS) potential was chosen for the intermolecular interactions. Surrounded by coexisting vapor, the droplets were first equilibrated at a temperature of T=110 K before being brought into contact with a distance of approximately a single molecule diameter. The coalescence process was studied under isothermal conditions with NVT simulation. Data of the coalescing droplets’ interface contours are stored in *.csv files, compressed as *.tar.xz archives that can be found in the contour/ subdirectories (Tree view). One *.csv file contains the data for a single interface contour described by spatial coordinate pairs x [nm] and r [nm]. The time stamp in the file name indicates the number of elapsed time steps, e.g.: *_ts000005000.csv => 5000 time steps = 2 fs x 5000 = 10 ps. The archive "early.tar.xz" contains data for the "early" stages of the coalescence process with fine time resolution (1 ps) and the archive "full.tar.xz" contains data for the "full" process with coarser time resolution (10 ps). A simple python script to plot coalescing droplets contours from the *.csv is provided in the subdirectory python/ (Tree view). It will generate contour plots and save them as *.pdf files. Additionally, a sequence of all contours will be created by merging the *.pdf files to a single file. Extracted from the interface contours, the evolution of the bridge radius r_b [nm] as well as back of drop positions x_bdl [nm] (left) and x_bdr [nm] (right) over time t [ns] can be found in the *_evo.tab files.