The LAGROBO functional representation of the atom-diatom interaction has been extended to the case of three different atom reactive systems having mio open product channels and an atom in an electronically excited state, The analytic formulation of the LAGROBO model is given and its application to the construction of the potential energy surface of the Li+FH and O(D-1)+HCl reactions are discussed, Reactive properties calculated on these surfaces using quasiclassical methods are compared with experimental findings.