title: Explanation of efficient quenching of molecular ion vibrational motion by ultracold atoms.
abstract: Buffer gas cooling of molecules to cold and ultracold temperatures is a promising technique for realizing a host of scientific and technological opportunities. Unfortunately, experiments using cryogenic buffer gases have found that although the molecular motion and rotation are quickly cooled, the molecular vibration relaxes at impractically long timescales. Here, we theoretically explain the recently observed exception to this rule: efficient vibrational cooling of BaCl(+) by a laser-cooled Ca buffer gas. We perform intense close-coupling calculations that agree with the experimental result, and use both quantum defect theory and a statistical capture model to provide an intuitive understanding of the system. This result establishes that, in contrast to the commonly held opinion, there exists a large class of systems that exhibit efficient vibrational cooling and therefore supports a new route to realize the long-sought opportunities offered by molecular structure.
authors.affiliation: Université de Bordeaux, Institut des Sciences Moléculaires, UMR 5255 CNRS, 33405 Talence, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Stoecklin
authors.affiliation: Université de Bordeaux, Institut des Sciences Moléculaires, UMR 5255 CNRS, 33405 Talence, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Halvick
authors.affiliation: Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France.
authors.forename: Mohamed Achref
authors.initials: MA
authors.lastname: Gannouni
authors.affiliation: Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France.
authors.forename: Majdi
authors.initials: M
authors.lastname: Hochlaf
authors.affiliation: Department of Physics, Temple University, 1925 N 12th Street, Philadelphia, Pennsylvania 19122, USA.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Kotochigova
authors.affiliation: Department of Physics and Astronomy, University of California, 475 Portola Plaza, Los Angeles, California 90095, USA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Hudson