Research Interests
1. Formation Mechanism of Microporous Materials
Our goal in this project is to unravel the complex process of microporous material formation at the molecular level, employing the power of molecular simulations. In our quest to gain a deep understanding of this formation mechanism, we will be developing specialized forcefields tailored to the study of two distinct classes of materials: Zeolites and Metal-Organic Frameworks (MOFs). These materials exhibit remarkable properties, making them important in various applications, from catalysis to gas separation. By investigating the detailed aspects of their molecular assembly, we aim to uncover the underlying principles that govern their structure and porosity, ultimately providing valuable insights for the design and optimization of these essential materials. Additionally, we are keen on understanding how the selection of polymorphs occurs within these materials, shedding further light on their structural diversity and properties. Our research endeavors to bridge the gap between theory and experiments, helping the fundamental science that underpins these microporous materials' exceptional performance.
2. Method Development Related to Hydrophobic Hydration and Phase Behavior of Macromolecules
Conformational transitions of flexible molecules, especially those driven by hydrophobic effects, tend to be hindered by desolvation barriers. For such transitions, it is thus important to characterize and understand the interplay between solvation and conformation. Using the recently developed dynamic indirect umbrella sampling (INDUS) method for sampling the number of solvent molecules, in the dynamical solvation shell of a flexible solute, we study the coil-to-globule or collapse transition of hydrophobic polymers/proteins solvated in polar and nonpolar solvent. Our overarching goal is to develop a framework related to the free energetics of solvent density fluctuations in the solvation shell of polymer or macromolecules to inform their phase behavior.
3. Mechanical Properties of Amorphous Ices
Our work on this topic investigates the transformations among different polymorphs of ice under high-pressure conditions, uncovering the kinetics and mechanisms that govern these transitions. By investigating the pressure-induced transformation of amorphous ices, we aim to shed light on the dynamic behavior of water in extreme environments, which holds critical implications for fields such as cryobiology and planetary science. Furthermore, we are also interested in the mechanical properties of these amorphous ices, exploring their response to various external forces and how these properties can be harnessed for applications ranging from materials science to climate modeling.
3. Molecular Dynamics Forcefield Development
At present, a primary focus of our research lies in the development of forcefields (FF) for molecular dynamics simulations involving small molecules within an aqueous environment. Among multiple empirical approaches available in the literature, the osmotic pressure method has proven to be an efficacious means for creating new FFs or enhancing existing ones. In a recent study, we used a straightforward yet highly effective parameter adjustment technique for two widely used non-polarizable FFs applied to the BMIMCl ionic liquid, making them compatible with the SPC/E water model. The resultant modified FFs exhibit a remarkable enhancement in their capacity to replicate experimental solution properties. Moreover, we are actively engaged in extending these models to encompass both all-atom and coarse-grained levels, enabling a more comprehensive exploration of their applicability in diverse molecular simulations.
5. Liquid-state anomalies and crystallization behaviors in semiconductor materials
Most semiconductor materials are made by melting them, so it's crucial to understand how they behave in their liquid form and how they turn into crystals. Germanium is unique because it can become a glass upon cooling. Surprisingly, there's not much research on the unusual behaviors of liquid germanium. Our work focuses on uncovering anomalies in thermodynamic, dynamic properties in the molten forms of both silicon and germanium and how this affects their transition into crystals. Similar anomalies can be seen in other liquids with a similar tetrahedral network structure, such as molten silica, certain p-bonded metallic liquids like tellurium, and fluids with special properties like core-softened or finite interparticle repulsion.
6. Structure-property relationships in water and other complex fluids
We employ a combination of molecular dynamics simulations, theoretical approaches, and experimental X-ray and neutron diffraction information to explore the connection between the structure and the thermodynamic and dynamic characteristics of diverse complex fluids, which encompass substances like water, room-temperature ionic liquids, and high-temperature ionic melts.
