We demonstrate that the Cartesian multipole interaction tenser may be
evaluated with recurrence relations analogous to the McMurchie-Davidso
n algorithm for calculation of electron repulsion integrals. With thes
e recursion relations all elements of the Cartesian multipole tenser t
hrough order L may be calculated in O(L(4)) CPU time, in contrast to c
urrent methods that scale as O(L(6)).