Chemistry Using Coulomb Crystals

Laser cooling of atomic ions has long been used as a tool in physics to explore quantum entanglement for applications in quantum computing and information. More recently, laser-cooled atomic ions have been used as a platform for studying cold chemistry. Here, we describe an experimental system called a “Coulomb crystal,” where laser-cooled ions are confined in traps at sufficiently low translational energies that they form an ordered structure. We then present a range of experiments undertaken using this platform, from studies of reactions with an atomic species to reaction systems of increased complexity, involving molecular ions and neutral molecules. We also describe a few spectroscopic studies enabled by Coulomb crystals before discussing some possible future directions of the field. This is not meant to be a comprehensive review of the entire field, but rather a sampling of the types of experiments that can be performed and the knowledge gained from these studies.