File Name : fig1_sm.pdf Caption : contour plots of the pes at different angular configurations for γ=γ_e. negative (blue lines) and positive (red lines) energies are separated in steps of 10 cm^-1 and 100 cm^-1, respectively. File Name : fig2_sm.pdf Caption : same as fig. 1 but for γ=80^o. File Name : fig3_sm.pdf Caption : same as fig. 1 but for γ=150^o. File Name : fig4_sm.pdf Caption : first v_{l₁m₁l₂l}(γ_e,r) radial coefficients of the sicsi-h₂ pes. File Name : fig5_sm.pdf Caption : analytical (lines) and ab initio (points) energies of the sicsi-h₂ complex at r=16 å for several values of γ, at a fixed configuration of φ, θ´ and φ´. these ab initio energies were not included in the fitting procedure. File Name : fig6_sm.pdf Caption : contour plots of the pes of sicsi-h₂ averaged over the h₂ orientation for φ=90^o at several values of γ. negative (blue lines) and positive (red lines) energies are separated in steps of 6 cm^-1 and 50 cm^-1, respectively.