The dependence of scattering length on van der Waals interaction and on the reduced-mass of the system in two-atomic collision at cold energies

TL;DR

This paper investigates how the scattering length in two-atomic collisions at cold energies depends on van der Waals interactions and the reduced mass, using advanced models to analyze elastic scattering.

Contribution

It introduces the application of SEM and MSEM models to study scattering length dependence on reduced mass and interatomic potential in cold atomic collisions.

Findings

Scattering length depends on reduced mass in hydrogen-like systems.

Long-range van der Waals effects influence scattering length.

Dependence observed varies with interatomic distance.

Abstract

The static-exchange model (SEM) and the modified static-exchange model (MSEM) recently introduced by Ray [1] is applied to study the elastic collision between two hydrogen-like atoms when both are in ground states considering the system as a four-body Coulomb problem in the center of mass frame, in which all the Coulomb interaction terms in direct and exchange channels are treated exactly. The SEM includes the non-adiabatic short-range effect due to electron-exchange. The MSEM added in it, the long-range effect due to induced dynamic dipole polarizabilities between the atoms e.g. the Van der Waals interaction. Applying the SEM code in different H-like two-atomic systems, a reduced mass dependence on scattering length is observed. Again applying the MSEM code on H(1s)-H(1s) elastic scattering and varying the minimum values of interatomic distance, the dependence of scattering length on the effective interatomic potential consistent with the existing physics are observed. Both these basic findings in low and cold energy atomic collision physics are quite useful and are being reported for the first time.