Long-range energy matrix elements have been calculated in the multipolar expansion approximation for all the molecular states dissociating to the three or four lowest asymptotes for the molecules LiNa, LiK, LiRb, LiCs, NaK, NaRb, NaCs, KRb, KCs and RbCs using the semi-empirical perturbative model we proposed recently. Two different assumptions have been investigated: including or excluding the spin-orbit effects within each atom. Full numerical results are presented for NaK and LiCs which have been chosen as examples. For the ten molecules in the non-interacting assumption the long-range coefficients C6 and C8 have been found for each state when neglecting atomic spin-orbit effects while the fitted value C*6 and C*8 are presented for each state when including atomic spin-orbit effects. When considering the interacting states, those dissociating to ns + n′s and to ns + 5d(Cs) are seen to be slightly perturbed while the states dissociating to ns + n′p and to np + n′s are significantly perturbed. The wavefunctions for the interacting 3Σ+, 3Π, 0+, 0−, 1, 2 states for the molecules NaK and LiCs are presented for various internuclear distances.