Persistent Thermal Inhomogeneities in a Gas-Cluster Mixture

TL;DR

This paper demonstrates that in gas-cluster mixtures, thermodynamics predicts a temperature suppression inside small clusters, affecting nucleation barriers and thermal radiation spectra, with significant implications for nucleation theory.

Contribution

It introduces a thermodynamic explanation for temperature inhomogeneities in gas-cluster mixtures, challenging existing kinetic models and impacting nucleation and radiation theories.

Findings

Temperature suppression inside small clusters confirmed

Reduced nucleation barrier due to thermal inhomogeneity

Altered thermal radiation spectrum predicted

Abstract

Surface tension of small grains and droplets makes them stable only at a much lower temperature than in bulk. This makes spontaneous nucleation unfavorable in many cases. Kinetic approaches are delicate in that one can easily generate models that do not agree with thermodynamics in the large N limit. Here it is shown that thermodynamics itself dictates a kind of temperature suppression inside each small cluster in any gas-cluster mixture. This gives a different perspective on the "translation-rotation" paradox in that this gives a time averaged steady state thermal inhomogeneity rather than just temporal fluctuations in the energy. This not only reduces the barrier to nucleation but also suggests a change in the thermal radiation spectrum from such a mixture that is not just a result of the inhibited radiation spectrum from Mie radiators. Either verification or refutation of this effect will be shown have important consequences for thermodynamics. An understanding of this effect will be essential to kinetic approaches to nucleation theory.