Theoretical Study Of The Dynamics And Potential Energy For Rb₂K Molecule

In the last decade, ultracold molecules are currently a topic of much interest in theatomic and molecular physics investigations. RbK, Rb2, which can be used inexperiment in ultracold temperature, has stimulated great interests in research. Thethree atom system Rb2K is composed of heteronuclear two atom system RbK and ahomonuclear diatomic molecule. The three atom Rb2K system plays an important rolein the study of diatomic molecular system and ultra cold molecules. We made a newpotential energy face (PES) using the multi-reference configuration interaction method.We calculated the Rb2+Kâ†'KRb+Rb dynamics based on the new PES in ourliterature.We calculated a large of points using MRCI. We used CASSCF calculation todetermine the molecular orbitals for the MRCI calculations in order to eliminate somespurious energy.59268energy points have been calculated for Rb2K employing basissets ECP10MDF for K, ECP28MDF for Rb.57000energy points, after analysis, werechosen to be fitted. The many-body expansion and Aguado and Paniagua function wereused to construct the APEFs. Then105parameters were obtained through nonlinearleast-squares algorithm method.We build two bodies of KRb and Rb2first. Murrell-Sorbie (MS) were used to fitthe two bodies and on the basis of this fit the three bodies. The Aguado Paniaguafunction and nonlinear least-squares algorithm were used to fitting the PES and westudied the complete dynamic properties. For the two body KRb, we use the results ofChen Kun et al [Kun Chen，Chuan-Lu Yang, Spectrochimica Acta Part A: Molecularand Biomlecular Spectroscopy.2012.99:57-61].Based on the new PES, we calculated the reaction cross-sections, correlationbetween vector k and k′correlation between vector j and j′, correlation among vector k,k′and j′for different collision energies of K+Rb2â†'KRb+Rb using quasi-classicaltrajectory. The stereodynamics for different collision energies (0.1kcal/mol to0.9kcal/mol) have been computed in precious literature. The calculation results showthat the main reaction scattering direction is forward scattering. Forward scattering isstrong for low Ecand gradually weakens with increasing Ec. The product rotationalangular momentum j′is not only aligned, but also oriented along the y-axis. It has been found that the orientation and orientation obviously enhance with the increasing Ec.The incident atom easily crosses the well and moves forward for large Ec.