Mean-Squared Energy Difference for Exploring Potential Energy Landscapes of Supercooled Liquids

DM Zhang and DY Sun and XG Gong, CHINESE PHYSICS LETTERS, 42, 056301 (2025).

DOI: 10.1088/0256-307X/42/5/056301

By extending the concept of diffusion to the potential energy landscapes (PELs), we introduce the mean-squared energy difference (MSED) as a novel quantity to investigate the intrinsic properties of supercooled liquids. MSED can provide a clear description of the "energy relaxation" process on a PEL. Through MSED analysis, we have obtained a characteristic time similar to that derived from structure analysis, namely tau alpha & lowast; . Further, we establish a connection between MSED and the feature of PELs, providing a concise and quantitative description of PELs. The relaxation behavior of energy has been found to follow a stretched exponential form. As the temperature decreases, the roughness of the accessible PEL changes significantly around a characteristic temperature Tx, which is 20% higher than the glass transition temperature Tg and is comparable to the critical temperature of the mode-coupling theory. More importantly, one of the PEL parameters is closely related to the Adam-Gibbs configurational entropy. The present research, which directly links the PEL to the relaxation process, provides avenues for further research of glasses.

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