Ab initio Study of the Potential Energy Surface and Stability of the Li2+(X2Σg+) Alkali Dimer in Interaction with a Xenon Atom

Abstract

The potential energy surfaces (PES) and the corresponding spectroscopic constants describing the interaction between the Li2+ (X2Σg+ ) alkali dimer in its ground state and the xenon atom are evaluated very accurately including the three-body interactions. We have used an accurate ab initio approach based on nonempirical pseudopotential, parameterized l-dependent polarization potential, and an analytic potential form for the Li+Xe interaction. The potential energy surfaces of the interaction Li2+ (X2Σg+ )-Xe have been computed for a fixed distance of the Li2+ (X2Σg+ ) and for an extensive range of the remaining two Jacobi coordinates, R and γ. The use of the pseudopotential technique has reduced the number of active electrons of Li2+ (X2Σg+ )Xe complex to only one electron. The core-core interaction for Li+Xe is included using the (CCSD(T)) accurate potential of Lozeille et al. (Phys Chem Chem Phys 4:3601, 2002). This numerical potential is adjusted using the analytical form of Tang and Toennies. Moreover, the interaction forces and the potential anisotropy are analyzed in terms of Legendre polynomials analytical representation of the potential energy surface (PES). To our best knowledge, there are no experimental nor theoretical study on the collision between the Li2+ (X2Σg+ ) ionic alkali dimer and the xenon atom. These results are presented for the first time.