Ultracold $O_2$+$O_2$ collisions in a magnetic field: on the role of the potential energy surface

Abstract

The collision dynamics of ${}^{17}{O}_2{(}^3{\Sigma }_g^{-}){+}^{17}{O}_2{(}^3{\Sigma }_g^{-})$ in the presence of a magnetic field is studied within the close-coupling formalism in the range between 10 nK and 50 mK. A recent global {\em ab initio} potential energy surface (PES) is employed and its effect on the dynamics is analyzed and compared with previous calculations where an experimentally derived PES was used [New J. Phys {\bf 11}, 055021 (2009)]. In contrast to the results using the older PES, magnetic field dependence of the low-field-seeking state in the ultracold regime is characterized by quite a large background scattering length, $a_{bg}$, and, in addition, cross sections exhibit broad and pronounced Feshbach resonances. The marked resonance structure is somewhat surprising considering the influence of inelastic scattering, but it can be explained by resorting to the analytical van der Waals theory, where the short range amplitude of the entrance channel wave function is enhanced by the large $a_{bg}$. This strong sensitivity to the short range of the {\em ab initio} PES persists up to relatively high energies (10 mK). After this study and despite quantitative predictions are very difficult, it can be concluded that the ratio between elastic and spin relaxation scattering is generally small, except for magnetic fields which are either low or close to an asymmetric Fano-type resonance. Some general trends found here, such as a large density of quasibound states and a propensity towards large scattering lengths, could be also characteristic of other anisotropic molecule-molecule systems.

24 pages, 8 figures

References in corpus (5)

• Quantum fluids of self-assembled chains of polar molecules
• Feshbach resonances in ultracold atomic and molecular collisions: threshold behaviour and suppression of poles in scattering lengths
• Cold N+NH Collisions in a Magnetic Trap
• OH hyperfine ground state: from precision measurement to molecular qubits
• Cold and ultracold NH--NH collisions in magnetic fields

Cited by in corpus (9)

• Collisions between cold molecules in a superconducting magnetic trap
• Long-range interactions in the ozone molecule: spectroscopic and dynamical points of view
• Efficient method for quantum calculations of molecule - molecule scattering properties in a magnetic field
• Cold collisions of heavy ${}^2\Sigma$ molecules with alkali-metal atoms in a magnetic field: Ab initio analysis and prospects for sympathetic cooling of SrOH${(}^2\Sigma )$ by Li(${}^2$S)
• Ultracold molecular collisions in combined electric and magnetic fields
• Total angular momentum representation for atom-molecule collisions in electric fields
• Elastic and inelastic collisions of ${}^2\Sigma$ molecules in a magnetic field
• Effect of the anisotropy on the glory structure of molecule-molecule scattering cross sections
• Ultracold collisions of the lithium monoxide radical