Research

Subtask 1: "Digital Twin" for Core Level Spectroscopy

The fascinating concept of "Digital Twin" originated from the industry, which was referring to a "digital copy of the physical asset".  For example, in its industrial settings, such asset can refer to a turbine, where we could use the data collected during the digital twin's simulated operations to minimize failure rates, to shorten development cycle, and to ensure that the product can be built. In other contexts, we could imagine having a digital twin of the organization, which facilitates the comprehensive planning of the processes in a business. "Digital Twin" is a broad concept that is applicable to a wide range of different fields. Embracing and moving into the digital era, our grand vision is to build a digital entity, that faithfully outputs the precise experimental outcomes such as measurable spectra, materials characterization data,  performances cycle, etc., with a current special focus on core-level spectroscopy.  The pillar stones for the success of our "Digital Twin" are a) the correct physics captured in electronic structure theory (Subtask 2), as well as b) accurate description of the thermodynamics and kinetics (Subtask 3).  

Subtask 2: Physics-Driven Electronic Structure Theory Development

Upon bombarding of a photon (either with tunable photon energy from a synchrotron source or a monochromatic tabletop source) to a given sample of interest, a pair of core-hole are created. This excited electron can further be ejected to the vacuum level (as in the case of X-ray Photoelectron Spectroscopy or XPS), or to the valence band (as in the case of X-ray Adsorption Spectroscopy or XAS), or to the valence band and then subsequently filling the empty core states (as in the case of Resonant inelastic X-ray scattering or RIXS). As one may naturally expect, physically and numerically accurate description of such core-excited processes demand more than routine ground state setups. We develop electronic structure code and efficient algorithms specialized for the description of core excitation in isolated molecular systems, condensed matter systems, as well as large-scale systems. These computational tools are actively helping out the interpretation of experimentally observed X-ray spectra in various scenarios.  

Subtask 3: Thermodynamics and Kinetics in Chemical Transformations

Chemical transformations and conversions plays a significant role in almost every aspect of modern society, such as transportation, utility, agriculture, and the manufacturing of a variety of consumer products.  Chemical transformations involved in the realistic systems are orders of magnitude more complex than the clean electronic/atomic picture described above in Subtask 2, yet we may be able to approximate these complex systems as a collection and network of fundamental chemical reactions dominated by thermodynamics and kinetics principles that control chemical reactivity in their pristine environment. Coupling the thermodynamics/kinetics aspects with the electronic structure aspects, we aim to uncover new insights in more complex environments, such as clusters, and nanoparticle surfaces which are frequently utilized in renewable energy applications.  

APXPS_15min_Jin Qian_subtitle.mp4

Jin's 15-mins talk at 7th International Ambient Pressure X-ray Photoemission Spectroscopy Workshop, December 2020

An updated list of published works can be found at google scholar.