Ground state potential energy curves for He–Kr, Ne–Kr, Ar–Kr, and Kr2: Coupled-cluster calculations and comparison with experiment

Ab initio calculations were performed with the coupled-cluster single and double excitations with perturbative triples correction method using the augmented correlation consistent polarized triple, quadruple, and quintuple zeta basis sets [aug-cc-pVnZ $\text{(n=T,Q,5)]}$ for four complexes: He–Kr, Ne–Kr, Ar–Kr, ${\mathrm{Kr}}_2.$ For each complex and each basis set a fitted potential energy curve is given. The most accurate results were obtained with the aug-cc-pV5Z basis set supplemented with an additional $\text{(3s3p2d2\hspace{0.05em}f1g)}$ set of bond functions. Ab initio potentials were compared to experimental data and the best empirical potentials available. The agreement was good although calculated potentials were found to be too shallow. To better reproduce spectroscopic data, ab initio potentials were modified using a nonlinear least-squares procedure. The modified potentials were developed for He–Kr, Ne–Kr, Ar–Kr, and ${\mathrm{Kr}}_2,$ as well as Ne–Ar and ${\mathrm{Ar}}_2.$ They all compare favorably with the best available empirical potentials.