Femtosecond PTHB spectroscopy was expected to demonstrate the existence of
distinct s-p absorption subbands originating from the three nondegenerate
p-like excited states of hydrated electron in anisotropic solvation cavity. Yet
no conclusive experimental evidence either for this subband structure or the
reorientation of the cavity on the picosecond time scale has been obtained. We
demonstrate that rapid reorientation of s-p transition dipole moments in
response to small scale motion of water molecules is the likely culprit. The
polarized bleach is shown to be too small and too short lived to be observed
reliably on the sub-picosecond time scale.Comment: 10 pages + 3 figures + supplement, will be submitted shortly to Chem.
Phys. Let