Ultracold collisions of polar molecules: thresholds effects

Coupled-channel equations with an interaction that includes only the dipolar part are solved in the paper. In this model only two constants (rotational constant and dipole moment) are required to define a collisional dynamics for a given collision kinetic energy (E) and electric field. Both fermionic and bosonic species with different constants were analyzed. The calculations demonstrate that the Born approximation is valid for a description of the threshold laws for both elastic and inelastic cross sections. It is expected an ultracold gas of fermionic polar molecules to be stable against collisions, whereas a bosonic gas may not be stable.