Ab initio determination of polarizabilities and van der Waals   coefficients of Li atoms using the relativistic CCSD(T) method
  We report a new technique to determine the van der Waals coeffcients of lithium (Li) atoms based on the relativistic coupled-cluster theory. These quantities are determined using the imaginary parts of the scalar dipole and quadrupole polarizabilities, which are evaluated using the approach that we have proposed in [1]. Our procedure is fully ab initio, and avoids the sum-over-the-states method. We present the dipole and quadrupole polarizabilities of many of the low-lying excited states of Li. Also, the off-diagonal dipole and quadrupole polarizabilites between some of the low-lying states of Li are calculated. 
L. W. Wansbeek, B. K. Sahoo, R. G. E. Timmermans, B. P. Das, and D.   Mukherjee