Degree of Initial Hole Localization/Delocalization in Ionized Water Clusters

The electronic structure of ionized bulk liquid water presents
a number of theoretical challenges. Not the least of these is the
realization that the detailed geometry of the hydrogen bonding network
is expected to have a strong effect on the electronic couplings between
water molecules and thus the degree of delocalization of the initially
ionized system. This problem is approached from a cluster perspective
where a high-level coupled cluster description of the electronic structure
is still possible. Building on the work and methodology developed
for the water dimer cation [J. Phys. Chem. A 2008, 112, 6159], the character and spectrum
of electronic states of the water hole and their evolution from the
dimer into higher clusters is presented. As the time evolution of
the initially formed hole can in principle be followed by the system’s
transient absorption spectrum, the state spacings and transition strengths
are computed. An analysis involving Dyson orbitals is applied and
shows a partially delocalized nature of states. The issue of conformation
disorder in the hydrogen bonding geometry is addressed for the water
dimer cation.