The central research theme of this lab is in the application of first principles methods to solve technological, environmental, or energy-related issues.

Research Interests

1. A theoretical characterization of the molecular and electronic structures, spectroscopic and thermochemical properties of chemical species, in their ground and excited states
2. The chemical reactivity, including the detailed kinetics and mechanisms, of several families of compounds and nanomaterials 
Calculated results allow us to identify novel reactive intermediates, mechanisms and phenomena, and to propose appropriate chemical models and concepts that could rationalize experimental facts. While our goal is to understand the behavior of chemical species at the molecular level, our ambition remains an a priori prediction of their properties and transformations in the real world.

Doped Silicon Clusters

 Silicon has been and continues to be one of the most widely used  elements in various applications such as solar cells and  microelectronics. Consequently, the chemical and physical  properties of nanometer sized silicon species have been intensively  studied for several decades. Nonetheless, the structures of some  small clusters, such as Si8+, could only recently be established in  combined experimental and theoretical work. Incorporation of  transition metal (TM) dopant atoms in silicon clusters has been  conjectured as a promising way of tailoring the optoelectronic  properties and the stability of silicon clusters. Elements from almost  every group of the periodic table are considered as dopant. Doping with magnetic atoms to realize magnetic nanometer sized silicon particles is of particular interest for a wide range of disciplines, including magnetic fluidics, biotechnology, magnetic resonance imaging, and data storage. Most importantly, the potential applications of spin-based electronic devices urge more research on magnetic semiconductors. For this purpose, we investigate in this project systematically the structure and bonding of the binary Si-based clusters with a variety of the elements.

Binary Boron Clusters

Binary clusters based on B are intriguing systems in part due to their interesting, but unusual, properties and potentially important applications in the fields of semiconductor materials and thermoelectric devices, and also in medicine. In this project, the geometrical and electronic structure, the chemical bonding and in particular the aromaticity of mixed clusters BnM where M are alkali and alkaline earth metals, and transition metals are investigated theoretically. We consider the BnM clusters with a large range of sizes, in particular the 'boron buckyball' (B₈₀) derivatives.

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3. Impact of alternative fuels on combustion kinetics

The goal of this research is to develop detailed chemical models which will be used to quantitatively characterize the impact of alternative fuels on combustion kinetics. We have been interested in Fischer-Tropsch fuels and biologically-derived diesels, especially at low temperatures (< 1000 K) where the fuel ignition behavior plays a role.
To understand the low-temperature oxidation chemistry of fuels, a systematic study on smaller systems (referred to as surrogate molecules, having similar chemical functional groups to those found in real fuel molecules) will be carried out using accurate electronic structure calculations and statistical mechanics methods. Specifically, this project will target reactions between surrogate radicals and molecular oxygen, which are crucial in low-temperature oxidation and auto-ignition processes. The improved understanding obtained from these surrogates will be generalized in terms of rate estimation rules, allowing us to effectively construct improved detailed kinetic models for real fuel molecules. Such models will then be used to quantitatively characterize the impact of alternative fuels as replacements or supplements for crude-oil-derived fuels on emissions as well as performance of conventional engines/turbines.

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4. Thermochemical conversion of biomass

The goal of this research is to construct detailed kinetic mechanisms for modeling/simulation of biomass thermochemical conversion processes, including gasification and pyrolysis, to increase overall conversion efficiency and decrease capital and operating costs. Currently, we focus our efforts on the pyrolysis process, and in particular on molecular weight growth which leads to coke formation.
The initial step of biomass thermal conversion involves the primary decomposition of the lignocellulosic matrix, one of the main components of which is lignin. In terms of molecular structure, lignin contains single-aromatic rings that might serve as starting places for molecular weight growth. Therefore, understanding how lignin breaks under pyrolysis conditions can help us in finding better ways to reduce the tar formation route by either reducing the rate of molecular weight growth or by selectively reducing the concentration of tar once formed. Selected model compounds, which represent the bonds and interlinkages commonly found in lignin, will be studied using accurate electronic structure calculations and statistical mechanics methods. This simplifies the effort by dealing with smaller systems that can be studied in more detail, and results can later be applied and extended to larger, more complex and real systems.

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5. Computational Design of Novel Catalysts/Materials

The purpose of this research is to design better catalysts/materials for complex chemical/physical processes using first-principles density functional theory (DFT) methods. With a statistical mechanics tool currently developed for gas-surface reactions in the group, micro-kinetic mechanisms for such processes will be constructed in an attempt to bridge fundamental chemistry/physics and surface reaction engineering.
DFT methods are employed to study adsorption/desorption as well as conversion of the species involved in the processes. Calculation results will allow us to evaluate mechanisms on the surface considered and their applications, energetically.  To give a more complete picture, the micro-kinetic mechanisms will be constructed by means of statistical mechanics. These micro-kinetic mechanisms, once validated, will be used to effectively model the applications in real operational conditions. 

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6. Code development
Computational tools have been developed in order to assist the efforts above.