Linac Coherent Light Source

The undulator converts the motion of high-energy electron bunches into coherent X-ray radiation. As the bunches travel through this structure, their motion generates the intense pulses required for measurements at atomic length and ultrafast time scales. Tuning the resulting radiation allows researchers to select conditions suited to imaging or spectroscopy, depending on the chemical question.

Ultrashort pulses provide snapshots during a reaction rather than only before and after it. In photochemical reactions and catalysis, time-resolved measurements can follow bond rearrangements, detect transient intermediates, and help reconstruct reaction pathways. This temporal information links rapidly changing molecular structures and electronic states with the chemical function observed during energy conversion or catalytic activity.

Imaging primarily addresses molecular structure, whereas spectroscopy probes electronic states. Linac Coherent Light Source radiation can be tuned for either measurement mode, so researchers can examine where atoms are arranged and how electronic properties change. Using the appropriate mode helps connect structural observations with electronic behavior, providing a more complete picture of molecular transformations and chemically active materials.

A chemistry experiment begins with high-energy electron bunches moving through the undulator to generate coherent X-ray pulses. The radiation is then tuned for the intended imaging or spectroscopy measurement, and time-resolved data are collected to examine a chemical process. Comparing observations across reaction times can reveal transient intermediates, bond rearrangements, and the sequence of a reaction pathway.

It is especially valuable when light-driven chemistry produces short-lived molecular states or rapid bond changes. The facility's ultrashort pulses can capture these transient stages during photochemical reactions, allowing researchers to relate evolving molecular structures and electronic states to the reaction pathway. That information supports more detailed explanations of how light initiates chemical change.

Measurements can show how molecular structures and electronic states evolve while a catalytic process proceeds. These observations help researchers connect molecular-scale dynamics with chemical function, which is important for interpreting catalytic behavior. More broadly, the resulting evidence can improve models of energy conversion and materials behavior by showing how transient changes relate to larger chemical outcomes.