Metastable Electrons, High-Mobility Solvent Anions, and Charge Transfer Reactions in Supercritical Carbon Dioxide

Autor:	Myran C. Sauer, I. A. Shkrob and
Rok vydání:	2001
Předmět:	chemistry.chemical_classification Chemistry Binding energy Analytical chemistry Activation energy Electron Electron acceptor Photon energy Surfaces Coatings and Films Ion Solvent Photoexcitation Materials Chemistry Physical and Theoretical Chemistry
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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