Condensed Phase and Interfacial Chemical Physics
For the first time, scientists have built completely flat, two-layer ice. While theoreticians have predicted that such ices are formed by squeezing water molecules between two surfaces, scientists at Pacific Northwest National Laboratory and Ruhr-Universitat Bochum are the first to create it. The top image is two-layer ice with hexagonal symmetry. The middle image is a side view showing two flat layers of molecules with hydrogen bonds connecting the layers. The bottom image is a side view of normal, puckered hexagonal ice. Enlarge Image
Our work in condensed phase and interfacial chemical physics supports research that is nationally and internationally recognized for providing a fundamental understanding of molecular processes in condensed phases. This research addresses fundamental uncertainties in thermal and non-thermal (i.e., radiation) chemistry, interfacial molecular and ionic transport, and other processes in complex systems related to energy use, environmental remediation, and waste management.
We study model systems to better understand natural systems and guide the development of new materials and approaches for clean and efficient energy use. Another central feature is the development of experimental and theoretical methods with broad applications to research in the natural sciences.
Integrating theory and experimentation. Our research contains both theoretical and experimental elements. We conduct fundamental research on
- Interactions of atoms, molecules, and ions with photons and electrons in all states of matter
- The use of model systems and unique methods to understand chemical processes on surfaces, in condensed media, and at interfaces
- First-principle calculations and advanced methods for modeling and simulations closely coupled with experiments to extend our understanding of chemical reactivity from the molecular scale to collective phenomenon in complex systems.
Rather than relying on empirical data to build models, our approach builds upon highly accurate first-principle calculations on prototype systems to develop models used in simulations of complex molecular systems such as liquid/liquid and liquid/solid interfaces. Many of these systems are not amenable to standard computational tools, so increases in computational capacity are not sufficient to solve the problems of interest. Therefore, we integrate computational tool development with applications to targeted problems.
An extra electron helps an ammonia molecule bump up to a hydrogen chloride molecule (top, middle) and pull the hydrogen from its chloride. This creates an electron-adorned ammonium chloride, an ionic salt (bottom right). The extra electron may find its way, temporarily, into the ammonium molecule (bottom left), forming a Rydberg radical.
Our experimental research provides a molecular-level understanding of chemistry at complex interfaces by
- implementing a multi-investigator approach to provide the breadth of expertise and capability required for investigation of complex interfacial chemical processes
- developing state-of-the-art research and analytical methods for characterizing complex materials of the types found in natural systems.
Model systems support detailed understanding of interfaces. Model systems are used to support detailed understanding and modeling of complex interfaces. Liquid/liquid and liquid/solid interfaces are built one molecule at a time to provide structures whose chemistry is understood and visualized at a level of detail and certainty not afforded by studies of naturally occurring, inhomogeneous systems. Both thermal processes and those activated by photons or electrons are studied. In a similar fashion, isolated ions are solvated by adding one solvent molecule at a time. X-ray spectroscopic methods are employed to study concentrated aqueous ionic solutions under extreme conditions. Advanced theory and modeling methods are used to model and interpret the results.
Contacts: Bruce Kay, Greg Schenter