Electron thermalization distance distribution and ion mobility in n-C6F14

1992 ◽  
Vol 70 (3) ◽  
pp. 915-918
Author(s):  
Takehisa Yoshinari ◽  
Gordon R. Freeman
Keyword(s):  
Refractive Index ◽  
Ion Mobility ◽  
Far Infrared ◽  
Distance Distribution ◽  
Liquid Density ◽  
Distance Distribution Function ◽  
Electric Field Dependence ◽  
Free Volume Model ◽  
Fluorine Compounds ◽  
Ion Yields

Electron thermalization distances in liquid n-C6F14 were estimated from the electric field dependence of the free-ion yields at 0.3 ≤ E (MV/m) ≤ 3.7 and densities 1564 ≤ d (kg/m3) ≤ 1951; the latter correspond to 335.4 ≥ T (K) ≥ 191.3. The distance distribution function that best fits the data has a Gaussian body and power tail (YGP), the same as in n-alkanes and in C6F6 and SF6, but different from those in the liquids N2, CO, and CS2. The latter apparently capture electrons at higher energies than do the fluorine compounds. The static relative permittivity of liquid n-C6F14 was measured as a function of temperature and compared with the square of the refractive index and the Debye and Clausius–Mosotti equations. Atomic polarization appears to contribute 6% to the refractive index in the far infrared. Cation mobilities at temperatures 335.4 ≥ T (K) ≥ 191.2 are fitted by the free volume model, with v0 = 1.71 × 10−4 m3/mol and Ev = 3.24 kJ/mol. Keywords: electron, ion, liquid density, permittivity, mobility, n-C6F14, thermalization distance.

Electron energy loss in fluids: Thermalization distances in liquid and gaseous sulfur hexafluoride

1990 ◽  
Vol 68 (9) ◽  
pp. 925-929 ◽  
Author(s):  
G. Ramanan ◽  
Norman Gee ◽  
Gordon R. Freeman
Keyword(s):  
Sulfur Hexafluoride ◽  
Electron Pair ◽  
Electron Attachment ◽  
Distance Distribution Function ◽  
Electric Field Dependence ◽  
Free Ion ◽  
Gaseous Sulfur ◽  
Ion Yields ◽  
Electron Energy Loss ◽  
Radiation Passing

Ionizing radiation passing through a fluid produces an ion–electron pair by knocking an electron off a molecule. The electron possesses excess energy, which it loses in collisions with molecules as it moves away from the ion. These are stochastic processes. The distance travelled during thermalization determines the probability that the electron ultimately escapes the Coulombic field of the ion to form freely diffusing ions. Free-ion yields were measured in X-irradiated sulfur hexafluoride at 5.7 ≤ d(kg m−3) ≤ 1860, corresponding to the vapor and liquid at 202.8 ≤ T(K) ≤ 324.1. (The critical fluid has dc = 730 kg m−3 and Tc = 318.7 K). The electric field dependence of the yield was best fitted using an electron thermalization distance distribution function F(y) that was Gaussian with a power tail. The most probable thermalization distance bGP was estimated at each density. The density-normalized electron-thermalizing ability of the fluid decreased with increasing gas density and was independent of density in the liquid phase. The dependence is different from those observed in hydrocarbons and might reflect a density effect on the energy dependence of the electron-attachment reaction.

scholarly journals Broadband spectroscopy of astrophysical ice analogues

2019 ◽  
Vol 629 ◽  
pp. A112 ◽  
Author(s):  
B. M. Giuliano ◽  
A. A. Gavdush ◽  
B. Müller ◽  
K. I. Zaytsev ◽  
T. Grassi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Time Domain ◽  
Complex Refractive Index ◽  
Far Infrared ◽  
Infrared Region ◽  
Thz Radiation ◽  
The Real ◽  
Thz Range ◽  
The Time Domain

Context. Reliable, directly measured optical properties of astrophysical ice analogues in the infrared and terahertz (THz) range are missing from the literature. These parameters are of great importance to model the dust continuum radiative transfer in dense and cold regions, where thick ice mantles are present, and are necessary for the interpretation of future observations planned in the far-infrared region. Aims. Coherent THz radiation allows for direct measurement of the complex dielectric function (refractive index) of astrophysically relevant ice species in the THz range. Methods. We recorded the time-domain waveforms and the frequency-domain spectra of reference samples of CO ice, deposited at a temperature of 28.5 K and annealed to 33 K at different thicknesses. We developed a new algorithm to reconstruct the real and imaginary parts of the refractive index from the time-domain THz data. Results. The complex refractive index in the wavelength range 1 mm–150 μm (0.3–2.0 THz) was determined for the studied ice samples, and this index was compared with available data found in the literature. Conclusions. The developed algorithm of reconstructing the real and imaginary parts of the refractive index from the time-domain THz data enables us, for the first time, to determine the optical properties of astrophysical ice analogues without using the Kramers–Kronig relations. The obtained data provide a benchmark to interpret the observational data from current ground-based facilities as well as future space telescope missions, and we used these data to estimate the opacities of the dust grains in presence of CO ice mantles.

Analytical solution of the PELDOR inverse problem using the integral Mellin transform

2017 ◽  
Vol 19 (48) ◽  
pp. 32381-32388 ◽  
Author(s):  
Anna G. Matveeva ◽  
Vyacheslav M. Nekrasov ◽  
Alexander G. Maryasov
Keyword(s):  
Inverse Problem ◽  
Distribution Function ◽  
Analytical Solution ◽  
Short Distance ◽  
Mellin Transform ◽  
Distance Distribution ◽  
Distance Distribution Function ◽  
Distance Range ◽  
Model Free ◽  
Model Free Approach

The model-free approach used does not introduce systematic distortions in the computed distance distribution function between two spins and appears to result in noise grouping in the short distance range.

Refractive index of flames in the far infrared

1973 ◽  
Vol 6 (6) ◽  
pp. 774-780 ◽  
Author(s):  
G Hubner ◽  
A R Jones
Keyword(s):  
Refractive Index ◽  
Far Infrared

Low energy electron ranges in liquids: determination by nonhomogeneous kinetics

1977 ◽  
Vol 55 (11) ◽  
pp. 2050-2062 ◽  
Author(s):  
J.-P. Dodelet
Keyword(s):  
Critical Temperature ◽  
Melting Point ◽  
Distribution Functions ◽  
Liquid Density ◽  
Range Distribution ◽  
Total Ionization ◽  
Free Ion ◽  
Drastic Increase ◽  
Pass Through ◽  
Ion Yields

Free ion yields have been measured in four hydrocarbon liquids: n-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, Gtot, 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 Gtot 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 about the behaviour of epithermal electrons in the four alkane liquids from the melting point up to the critical temperature.(1) 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 the critical temperature.

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