Ab initio calculations of spectroscopic constants and properties of BeLi

We have calculated the ground state spectroscopic constants and the molecular properties, of a molecular ion BeLi + , such as dipole moment, quadrupole moment and dipole polarizability at different levels of correlation: many-body perturbation theory (MP2), coupled cluster method with single and double excitations (CCSD) and CCSD with perturbative triples (CCSD(T)). The correlation consistent polarized valence cc-pVXZ (X=D, T, Q) basis sets and also their augmented counterparts are used together with the non-relativistic and relativistic Hamiltonians. The results are extrapolated to the complete basis set limit (CBS) using exponential-Gaussian function. Thus, accurate and reliable results for BeLi + with the most conservative error estimates on them are reported.