  Long range electrostatic and van der Waals coefficients up to terms of order
R-8 have been evaluated by the sum over states method using ab initio and time
dependent density functional theory. We employ several widely used density
functionals and systematically investigate the convergence of the calculated
results with basis set size. Static electric moments and polarizabilities up to
octopole order are also calculated. We present values for Li2 through K2 which
are in good agreement with existing values, in addition to new results for Rb2
and Cs2. Interaction potential curves calculated from these results are shown
to agree well with high level it ab initio theory.
