Cold physics and chemistry: Collisions, ionization and reactions inside helium nanodroplets close to zero K

This review provides a comprehensive overview of the applications of helium nanodroplets in the study of ensembles of atoms and molecules, i.e. clusters and complexes. These clusters and complexes must form through collisions inside helium nanodroplets, hence the title of this review. It also provides a particularly detailed overview of the many studies of ions, both positive and negative, that have been carried out in helium nanodroplets.