Deposition of model chains on surfaces: anomalous relation between flux and stability

TL;DR

This study uses Monte Carlo simulations to explore how flux influences the stability of model chains on surfaces, revealing an unexpected increase in energy with decreasing flux under certain conditions, contrasting with cooling experiments.

Contribution

It uncovers an anomalous flux-energy relationship in model chain deposition, providing insights into the stability of configurations formed via flux versus cooling.

Findings

Energy increases with decreasing flux in certain temperature and flux ranges.

No anomaly observed in cooling experiments.

Flux experiments can produce more stable configurations than cooling.

Abstract

Model chains are studied via Monte Carlo simulations which are deposited with a fixed flux on a substrate. They may represent, e.g., stiff lipophilic chains with an head group and tail groups mimicking the alkyl chain. After some subsequent fixed simulation time we determine the final energy as a function of flux and temperature. Surprisingly, in some range of temperature and flux the final energy increases with decreasing flux. The physical origin of this counterintuitive observation is elucidated. In contrast, when performing equivalent cooling experiments no such anomaly is observed. Furthermore, it is elaborated whether flux experiments give rise to configurations with lower energies as compared to cooling experiments. These results are related to recent experiments by the Ediger group where very stable configurations of glass-forming systems have been generated via flux experiments.