title: Rubidium polyhydrides under pressure: emergence of the linear H3(-) species.
abstract: The structures of compressed rubidium polyhydrides, RbH(n) with n>1, and their evolution under pressure are studied using density functional theory calculations. These phases, which start to stabilize at only P = 2 GPa, consist of Rb(+) cations and one or more of the following species: H(-) anions, H(2) molecules, and H(3)(-) molecules. The latter motif, the simplest example of a three-center four-electron bond, is found in the most stable structures, RbH(5) and RbH(3) , which metallize above 200 GPa. At the highest pressures studied, our evolutionary searches find an RbH(6) phase which contains polymeric (H(3)(-))(∞) chains that show signs of one-dimensional liquid-like behavior.
authors.affiliation: Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14260-3000, USA.
authors.forename: James
authors.initials: J
authors.lastname: Hooper
authors.forename: Eva
authors.initials: E
authors.lastname: Zurek