| A study is presented of the dynamics of an excess electron solvated in clusters of polar molecules. Dynamics following charge-transfer-to-solvent (CTTS) in I-(water)n clusters ( n=3-28) are examined. Large (methanol)n - clusters are examined by photoelectron spectroscopy, and the dynamics following excitation of the excess electron in this system are considered.;For all I-(water)n clusters with n>4, creation of the CTTS state is followed by rearrangment of the solvent water molecules to stabilize the excess electron by several hundred millielectron volts. This process takes place on a timescale of several hundred femtoseconds to ∼1 ps, and is accompanied by an increase in photodetachment cross-section from the CTTS state. Subsequently, the iodine atom leaves the cluster, on a timescale of tens of picoseconds. All clusters show decay of the CTTS state via excited state autodetachment on a timescale of a few hundred femtoseconds for n=3 to a few nanoseconds for n=8-10.;Photoelectron spectra of (methanol)n - clusters show two isomers. A more tightly bound isomer is seen for n>140, bound by over 2 eV, with the vertical detachment energy (VDE) increasing with increasing cluster size, and shows evidence of an excited state accessible at 1.55 eV. A more loosely bound isomer is seen for n>70 and is bound by less than half an electron volt, also with VDE increasing with cluster size. Dynamics following excitation in methanol I for n∼150-550 show considerable similarity to those reported for water clusters in the much smaller size range of n=25-150. Internal conversion occurs with a lifetime of a few hundred femtoseconds, extrapolating linearly with 1/n to 150 fs at the bulk limit. Vibrational relaxation on the ground state occurs with a lifetime of ∼750 fs for all cluster sizes. |
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