Events in physical chemistry.

What drives nighttime chemistry?

Chemistry in the Earth’s atmosphere is driven mainly by sunlight. Indeed, this chemistry is termed atmospheric photochemistry. However, chemistry does not stop at night! I will describe some of the major processes at night and attempt to answer the question: “What is the energy source for nighttime chemistry when there is no sunlight? I will use examples from various laboratory measurements, field studies, and calculations.

Artificial two-dimensional superlattices: synthesis and properties

Two-dimensional (2D) materials and their engineered lattices offer exciting opportunities for next-generation electronic, optoelectronic, and electrochemical devices. Yet, studies of high-quality heterostructures have been largely constrained to microscopic flakes. Here, we present scalable, controllable top-down methods that transform a wide range of van der Waals (vdW) single crystals into twisted moiré superlattices with high yield, exceptional uniformity, and macroscopic dimensions from millimeters to centimeters.

Advancing attosecond science to liquids and chiral molecules

Attosecond science is maturing into a transformative tool for measuring and understanding ultrafast electronic and structural dynamics, but its extension to complex systems is hampered by challenges of both technical and fundamental nature. Our group has pioneered attosecond spectroscopy in liquids. Attosecond photoelectron spectroscopy with liquid microjets has been developed and applied to measure delays of 50-70 attoseconds between the photoemission from liquid vs. gas-phase water¹.

Developing a Mechanistic Picture of the Synthesis and Assembly of Inorganic Nanomaterials

The properties of inorganic nanoscale particles are largely determined by their surfaces, as the fraction of surface atoms can approach unity as the size approaches 1 nm. As a result, the coordination of ligands to the particle surface can quickly become the dominant energetic contribution to the system and therefore provides an opportunity to use molecular design principles to control the formation of well-defined inorganic materials.

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