Hello: In some books I have found for the quadrupolar moment Q=1/2(Integral) and in others Q=Integral, in atomic units. I would like to know wich one is used in Molpro package. Thanks Maikel Ballester Integral =\int (3r_ir_j-r^2\delta_i^j)\rho(\overrightarrow r) d^3\overrightarrow r