Low energy electron ranges in liquids: determination by nonhomogeneous kinetics

Abstract

J.-P. DODELET. Can. J. Chem. 55. 2050Chem. 55. (1977. Free ion yields have been measured in four hydrocarbon liquids: 71-pentane, cyclopentane, neopentane, and neohexane. Each liquid has been studied from room temperature or below up to the critical temperature. Theoretical curves have been calculated using the relation between the free ion yields and the external field strength derived by Terlecki and Fiutak on the basis of an equation by Onsager. Two popular electron range distribution functions, Gaussian and exponential, have been shown not to be an adequate representation of the reality as far as the model used for the calculations is concerned. In order to fit experimental points, both range distribution functions would require a drastic increase in the total ionization yield, GI,,, with temperature increase. This would mean an unrealistic decrease of the ionization potential of the molecule from the melting point up to the critical temperature.It is possible to keep GI,, quite constant and within the range of values obtained by other techniques by extending the Gaussian range distribution function with a (range)-3 probability tail. The most probable range can be normalized for the liquid density. This parameter has been used to obtain information a b o~~t the behaviour of epithermal electrons in the four alkane liquids from the melting point up to the critical temperature.( I ) Normalized penetration ranges of epithermal electrons are dependent on the structure of the molecule in the entire liquid range but differences are smaller at critical than at low temperatures.(2) Normalized penetration ranges of epithermal electrons pass through a maximum in the liquid phase for neopentane, neohexane, and cyclopentane. No maximum is observed for n-pentane.(3) There is no drastic change in the behaviour of epithermal electrons in these alkanes at t h e critical temperature.J.-P. DODELET. Can. J. Chem. 55.2050Chem. 55. (1977. Les rendements en ions libres ont Cte mesurks dans quatre hydrocarbures liquides: le npentane, le cyclopentane, le neopentane et le nCohexane. Chaque hydrocarbure a ete etudie depuis une temperature egale ou infkrieure a celle du laboratoire jusqu'a la temperature critique. Les courbes thtoriques ont et6 calculCes en utilisant la relation, dtduite par Terlecki et Fiutak d'apres une equation d'onsager, entre les rendements en ions libres et le champ Clectrique applique. Deux distributions des parcours electroniques, I'une de type gaussien, I'autre exponentiel, trks populaires dans la litterature, ont ete utilisees dans les calculs et n'ont pas donne satisfaction dans le cadre de ce modele. En effet, pour ces deux distributions, une bonne coincidence entre les calculs et l'experience requerrait, lorsque la temperature augmentait un accroissement considerable du rendement total en ions, GI,,, ce qui aurait signifie une diminution constante, tres peu probable, du potentiel d'ionisation de la molecule a partir du point de fusion jusqu'a la temperature critique. I1 est possible de maintenir GI,,, r...

Electron mobilities in alkanes through the liquid and critical regions

“…he-density normalized penetration ranges of the secondary electrons in these liquids also pass through maxima (58). The range maxima occur at temperatures slightly higher than those of the mobilitj~ maxima (Fig.…”

Concerning the spectra and solvation process of electrons in liquid butanols

“…The mechanism of electron energy degradation in irradiated fluids continues to attract interest (1) after many years of investigation (2)(3)(4)(5)(6)(7)(8). Events at energies 2 10 eV are moderately well understood (1)(2)(3)(4).…”

“…Events at energies 2 10 eV are moderately well understood (1)(2)(3)(4). At lower energies indirect information can be obtained from the thermalization ranges of the secondary electrons (4)(5)(6)(7)(8). In polar and many nonpolar liquids the electrons ultimately become localized and, through further energy loss processes, settle into the solvated state, which is in thermal equilibrium with 'Assisted financially by the National Research Council of Canada.…”