The central water and the first solvation shell are described with the fully uncontracted 6-311+G(3df) basis on oxygen and the 6-311G basis on hydrogens. The rest of the waters in the QM system are treated with a smaller basis-6-311G* in protocols 1 and 2, and 6-31G in protocol 3. The rest of the waters are described by point charges. We freeze all the oxygen cores in the QM system in the CVS-EOM-IP calculations and request the number of IEs equal to the number of oxygen atoms in the QM system. We then select the IE of the central water.