C. Amovilli et al., Inhomogeneous electron liquid: Differential equation satisfied by diagonalelement of Coulomb bound s-state green function, PHYS CHEM L, 37(4), 1999, pp. 475-478
Because of density functional theory, attention has shifted from density ma
trices and Green functions to their diagonal elements. Here, an explicit pa
rtial differential equation is given for the diagonal elements of the bound
state Green function for the a-states only. Relation to earlier work in te
rms of Whittaker functions is briefly discussed, for the Coulomb field case
.