Ultracold atom-molecule collisions and bound states in magnetic fields: Tuning zero-energy Feshbach resonances in He-NH ({sup 3}{sigma}{sup -})

Journal Article · Thu Feb 15 04:00:00 EST 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.75.022702· OSTI ID:20982116

Gonzalez-Martinez, Maykel Leonardo; Hutson, Jeremy M ^[1]

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1. Departamento de Fisica General y Matematicas, InSTEC, Habana 6163 (Cuba)

We have generalized the BOUND and MOLSCAT packages to allow calculations in basis sets where the monomer Hamiltonians are off diagonal and used this capability to carry out bound-state and scattering calculations on {sup 3}He-NH and {sup 4}He-NH as a function of magnetic field. Following the bound-state energies to the point where they cross thresholds gives very precise predictions of the magnetic fields at which zero-energy Feshbach resonances occur. We have used this to locate and characterize two very narrow Feshbach resonances in {sup 3}He-NH. Such resonances can be used to tune elastic and inelastic collision cross sections, and sweeping the magnetic field across them will allow a form of quantum control in which separated atoms and molecules are associated to form complexes. For the first resonance, where only elastic scattering is possible, the scattering length shows a pole as a function of magnetic field and there is a very large peak in the elastic cross section. For the second resonance, however, inelastic scattering is also possible. In this case the pole in the scattering length is dramatically suppressed and the cross sections show relatively small peaks. The peak suppression is expected to be even larger in systems with stronger inelasticity. The results suggest that calculations on ultracold molecular inelastic collisions may be much less sensitive to details of the potential energy surface than has been believed.

• OSTI ID: 20982116
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 75; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOM-MOLECULE COLLISIONS
ATOMS
BOUND STATE
CROSS SECTIONS
ELASTIC SCATTERING
FORECASTING
HAMILTONIANS
HELIUM 3
HELIUM 4
INELASTIC SCATTERING
MAGNETIC FIELDS
MOLECULES
MONOMERS
NITROGEN HYDRIDES
POTENTIAL ENERGY
RESONANCE
SCATTERING LENGTHS
SURFACES
TUNING