Large scale molecular simulations for multi-scale dynamics in glass forming liquids

2016 Fiscal Year Final Research Report

• Project/Area Number: 26400428
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Biological physics/Chemical physics/Soft matter physics
• Research Institution: Osaka University (2016); Niigata University (2014-2015)
• Principal Investigator: KIM Kang 大阪大学, 基礎工学研究科, 准教授 (20442527)
• Research Collaborator: KAWASAKi Takeshi
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: ガラス転移 / 過冷却液体 / 分子シミュレーション / 動的不均一性 / 低次元ランダム系 / ボンド切断法 / 熱振動

Outline of Final Research Achievements

A glassy system lacks the crystalline order and endows the random structure. Structural correlations cannot represent the dimensionality dependence. We need to examine dynamical aspects to clarify the dimensionality dependence. We demonstrated that fluctuation is dependent on the spatial dimensions, but the modality of inherent structural relaxation is similar between 2D and 3D. From large-scale molecular simulations, we clarified enhancement of 2D fluctuation taking place due to a mechanism similar to Mermin-Wagner theorem by direct calculation of the Debye-asymptote of the vibrational density of states. This also accounts for enhanced fluctuation recently observed in 2D systems. It leads to system-size dependent of the relaxation time and dynamic correlation length in the 2D system in terms of the density correlation functions. However, such size dependence is eliminated by introduction of an alternative correlator that characterizes relative rearrangement motions of the particles.

Free Research Field

統計物理学