Thermal accommodation coefficients for laser-induced incandescence sizing of metal nanoparticles in monatomic gases

The capabilities of time-resolved laser-induced incandescence (TiRe-LII), a combustion diagnostic used almost exclusively to measure soot primary particles, could potentially be extended to size aerosolized metal nanoparticles. In order to do this, however, it is necessary to characterize the thermal accommodation coefficient, a, which specifies the heat conduction rate between the laser-energized nanoparticles and the surrounding gas. This paper extends a molecular dynamics (MD) methodology to calculate a for Fe/He, Fe/Ar, Mo/He, and Mo/Ar systems. A comparative analysis of the results shows that a is most strongly influenced by the potential well between the gas molecule and nanoparticle surface. Finally, the MD-derived value for a is used to recover the nanoparticle size distribution for TiRe-LII measurements made on molybdenum nanoparticles in argon.