a:
link
In this paper, the effects of multipole moments of water on the solvation of ions (Na+ in this case) is researched. By studying the multipole moments, the charge distribution of the nuclei in the water molecule can be obtained and a model of water-water and water-ion interactions can be formed. This can for example be useful in biology, by explaining/modelling the transport of ions in living cells.
b:
The calculation of the multipole momenta in the two configurations on the left of the screen can be found in the pdf file I uploaded.