Metastable Electrons, High-Mobility Solvent Anions, and Charge Transfer Reactions in Supercritical Carbon Dioxide
Autor: | Myran C. Sauer, I. A. Shkrob and |
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Rok vydání: | 2001 |
Předmět: | |
Zdroj: | The Journal of Physical Chemistry B. 105:4520-4530 |
ISSN: | 1520-5207 1520-6106 |
Popis: | Time-resolved dc photoconductivity has been used to observe quasifree electrons and solvent radical anions in supercritical CO2 (ρc ≈ 0.468 g/cm3; Tc ≈ 31 °C). The electrons have lifetime τe 10 cm2/(V s). For ρ/ρc > 0.64, the product μeτe rapidly increases with the solvent density ρ, reaching 2.5 × 10-9 cm2/V at ρ/ρc ≈ 1.82. The mobility of the solvent anions exponentially increases with ρ, being 2−10 times higher than the mobilities of other ions. The activation energy of the solvent anion migration is 0.46 eV, whereas for solute ions, this energy is less than 20 meV. Electron detachment upon 1.0−3.5 eV photoexcitation of the solvent anion has been observed. The cross section of photodetachment linearly increases with photon energy above 1.76 eV end exhibits a shoulder at 2.82 eV; the spectrum is similar to photoelectron spectra of (CO2)n- clusters (n = 6−9) in the gas phase. Both the electrons and solvent anions react with nonpolar electron acceptor solutes whose gas-phase ele... |
Databáze: | OpenAIRE |
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