Molecules and Ions at Very Low Temperatures

The generation and study of 'cold' gas-phase molecules characterised by very low translational temperatures T trans ≤ 1 K is an upcoming field of research in physical chemistry which has received considerable attention over the past years. A particular interesting form of cold molecules are ensembles of cold localised cations in ion traps which form ordered structures known as 'Coulomb crystals'. The present article reviews the experimental methods used for the generation of atomic and molecular Coulomb crystals and highlights recent experiments which take advantage of their intriguing properties in order to study chemical reactions at very low temperatures with single-particle sensitivity.