Resonance Raman spectra of electrons solvated in liquid alcohols.
ABSTRACT Resonance Raman spectra of electrons solvated in liquid methanol, ethanol, and n-propanol are presented. At least five distinct solvent modes exhibit resonantly enhanced scattering, including the OH torsion, CO/CC stretches, the OH in-plane bend, methyl deformations, and the OH stretch. The 200-350 cm-1 frequency downshift of the OH stretch indicates a strong H-bond interaction between the electron and the hydroxyl group. The multiple modes including alkyl vibrations that are coupled to the electronic transition of the solvated electron reveal the extension of the electron's wavefunction into the alkyl solvent environment.
- SourceAvailable from: Jan R R Verlet[Show abstract] [Hide abstract]
ABSTRACT: Electron solvation in methanol anion clusters, (MeOH)(n) (-) (n approximately 70-460), is studied by photoelectron imaging. Two isomers are observed: methanol I, with vertical binding energies (VBE) ranging from 2-2.5 eV, and methanol II, with much lower VBE's between 0.2 and 0.5 eV. The VBE's of the two isomers depend linearly on n(-1/3) with nearly identical slopes. We propose that the excess electron is internally solvated in methanol I clusters, whereas in methanol II it resides in a dipole-bound surface-state. Evidence of an excited state accessible at 1.55 eV is observed for methanol I.The Journal of Chemical Physics 12/2006; 125(17):171102. · 3.12 Impact Factor
- Chemistry Letters - CHEM LETT. 01/2010; 39(7):668-670.
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ABSTRACT: The structural and electronic properties of an excess electron (EE) in the ionic liquid (IL) 1-methylpyridinium chloride were explored using ab initio molecular dynamics simulations and quantum chemical calculations to give an overall understanding of the solvation and transport behavior of an EE in this IL. The results show that the EE resides in cation pi*-type orbitals and that the electronic states can be characterized by the alternating appearance of localized and delocalized states during the time evolution. The characters of the EE electronic states are determined by the number of cations contributing to the LUMO of the IL. In a localized state one or two cations contribute to the LUMO of the bulk ionic liquid, while in the delocalized state the IL LUMO is composed of pi*-type orbitals spanning nearly all the cations in the cell. The arrangement and fluctuation-induced changes of the orbital components in the empty band produce an alternation of different states and leads to the migration of the excess electron. These findings can be attributed to the special features of the electronic structures and geometries of the IL, and they can be used to explain similarities and differences between pyridinium-based and imidazolium-based ILs in mediating electron migration.Physical Chemistry Chemical Physics 02/2010; 12(8):1854-61. · 4.20 Impact Factor