Unraveling the "Pressure-Effect" in Nucleation

TL;DR

This paper explains the ambiguous effects of inert gas pressure on nucleation rates by modeling the competition between nonisothermal effects and pressure-volume work, clarifying experimental contradictions.

Contribution

It introduces a model that accounts for both effects to explain and predict how inert gas pressure influences nucleation, unifying previous conflicting observations.

Findings

The model explains the varying effects of inert gas pressure on nucleation.

Results are supported by molecular dynamics simulations.

The findings have implications for natural and industrial nucleation processes.

Abstract

The influence of the pressure of a chemically inert carrier-gas on the nucleation rate is one of the biggest puzzles in the research of gas-liquid nucleation. Different experiments can show a positive effect, a negative effect, or no effect at all. The same experiment may show both trends for the same substance depending on temperature, or for different substances at the same temperature. We show how this ambiguous effect naturally arises from the competition of two contributions: nonisothermal effects and pressure-volume work. Our model clarifies seemingly contradictory experimental results and quantifies the variation of the nucleation ability of a substance in the presence of an ambient gas. Our findings are corroborated by results from molecular dynamics simulation and might have important implications since nucleation in experiments, technical applications, and nature practically always occurs in the presence of an ambient gas.