التفاصيل البيبلوغرافية
| العنوان: |
Effect of CH[sub 4] addition on excess electron mobility in liquid Kr. |
| المؤلفون: |
Borghesani, A. F., Folegani, M., Frabetti, P. L., Piemontese, L. |
| المصدر: |
Journal of Chemical Physics; 9/22/2002, Vol. 117 Issue 12, p5794, 8p, 8 Graphs |
| مصطلحات موضوعية: |
ELECTRON mobility, LIQUID methane |
| مستخلص: |
The mobility μ of excess electrons has been measured in liquid mixtures of Kr and CH[sub 4] as a function of the electric field up to E ≈ 10[sup 4] V/cm and of the CH4 concentration χ up to χ ≈ 10%, at a temperature T ≈ 125 K, fairly close to the normal boiling point of Kr (T[sub b] ≈ 120 K) [Nucl. Instrum. Methods Phys. Res. A 430, 277 (1997)]. We present here new data extending the previous set in the low E region. At small E, μ appears to be quite independent of χ. CH[sub 4] impurities prove to be less efficient in enhancing momentum transfer than liquified rare gas impurities Kr and Xe in liquid Ar. The dependence of μ on E at higher strengths is complicated. On the one hand, the addition of CH[sub 4] extends the range of E in which μ is field independent, by efficiently thermalizing the electrons. On the other hand, at the highest field, the presence of the impurities accomplishes a large increase of the electron drift velocity with respect to the pure liquid (up to a factor of 7 for the highest μ). Moreover, at intermediate values of E, where electrons are epithermal, there appears to be a crossover between two different behaviors of μ as a function of E. The electric field strength at the crossover, E[sup *], is well correlated with χ. The behavior of μ can be rationalized in terms of a gas-kinetic model proposed to explain its concentration dependence in the liquified rare gas mixtures Ar-Kr and Ar-Xe. This analysis suggests that the observed crossover is related to the excitation of the first vibrational level of CH[sub 4]. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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