Feshbach resonances and transition rates for cold homonuclear collisions between $^{39}\mathrm{K}$ and $^{41}\mathrm{K}$ atoms

Feshbach resonances and transition rates for cold homonuclear collisions between ${}^{39}K$ and ${}^{41}K$ atoms

M. Lysebo and L. Veseth

Phys. Rev. A 81, 032702 – Published 10 March 2010

Abstract

We report results from close-coupling calculations for homonuclear ultracold collisions between potassium atoms, using the most up-to-date Born-Oppenheimer potential curves. The present study includes both of the bosonic isotopes ${}^{39}K$ and ${}^{41}K$ . The $s$ -wave scattering lengths as functions of the magnetic field strength for collisions between atoms in identical and different hyperfine states are obtained. Several Feshbach resonances are located and characterized for both isotopes. Comparison with experiments, where such data are available, show excellent agreement. We also study weakly bound molecular states of the $K_{2}$ molecule in close relation to the calculated Feshbach resonances. Another objective of the present work is to study inelastic collisions in which the hyperfine states of the colliding atoms are changed. From this type of calculation we obtain transition rates as functions of the magnetic field strength. Finally, we discuss how such transition rates might be of importance for experimental work.