Investigation of Quantum Coherence and Correlated Dynamics Using Attosecond Spectroscopy

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Electron motion is fundamental to the natural and laboratory phenomena that govern our daily lives, examples being photosynthesis, chemical processes, electronic circuits, etc. Being elementary particles, electrons are extremely agile, and can move inside atoms, molecules and materials on the timescale of attoseconds, which is a billionth of a billionth of a second. To understand the functioning of physical, chemical and biological processes important to us, it is useful to be able to resolve and control the underlying fast electronic motion. Recently devised attosecond spectroscopy provides exactly such an opportunity, where attosecond duration light pulses can be used to strobe the dynamics of electrons. The researchers supported by this project will develop methods to study how electrons help to redistribute energy within molecules. Success along these directions could open up opportunities for direct control of chemical processes in complex molecules relevant for light harvesting and energy storage. The proposed program will therefore advance US scientific efforts in a frontier area of research, while training the next generation of scientists belonging to diverse backgrounds.This project aims for detailed investigation of quantum coherence and correlated electronic and nuclear dynamics using ultrafast light pulses. These studies will focus on what transpires at the quantum level, in terms of interactions between electrons, couplings between electrons and nuclei, and between molecules and the environment. The natural timescale for the evolution of electronic superpositions is in the femtoseconds to attosecond regime, so these investigations will involve the application of attosecond to femtosecond x-ray, extreme ultraviolet, and infrared light pulses. The scientific objectives of the project are: (1) Investigation of correlated decay dynamics of molecular excited states, (2) Study of coherent charge migration and decoherence mechanisms, and (3) Implementation of new techniques to study charge directed reactivity. These objectives will be achieved while training graduate and undergraduate students in the field of attosecond spectroscopy. Velocity map imaging and attosecond transient absorption techniques will be used in the proposed work. The far-reaching objective is to build bridges between the field of physics, and those of chemistry, biology and material sciences, paving the way for control of a variety of electron driven processes. The project will also conduct outreach by involving undergraduates and the local community, and by creating advanced research opportunities for members of under-represented groups.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.