Epithermal Electron Ranges and Thermal Electron Mobilities in Liquid Aromatic Hydrocarbons

Abstract

Radiolysis free ion yields were measured as functions of electric field strength and temperature in benzene, toluene, 1,2-, 1,3-, and 1,4-dimethylbenzene, 1,2,3-, 1,2,4-, and 1,3,5-trimethylbenzene, 1,2,3,4- and 1,2,4,5-tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, naphthalene, and anthracene. Secondary electron ranges bGP were estimated from the yields. The density-normalized ranges bGPd were almost constant, 34−38 × 10−8 g/cm2, from benzene up to the tetramethylbenzenes, then increased to 47 × 10−8 in pentamethyl- and 52 × 10−8 in hexamethylbenzene. In naphthalene and anthracene the normalized ranges were 32 and ∼20 × 10−8 g/cm2, respectively. Electron mobilities in the liquids at 293 K, and their activation energies, expressed in (cm2/V s, kcal/mol) were: benzene (0.114, 7.4); toluene (0.063, 3.4); 1,2-dimethylbenzene (0.018, 4.4); 1,3-dimethylbenzene (0.057, 4.5); 1,4-dimethylbenzene (0.062, —); 1,2,3-trimethylbenzene (0.022, 4.8); 1,2,4-trimethylbenzene (0.035, 4.3); 1,3,5-trimethyl-benzene (0.17, 3.2); 1,2,3,4-tetramethylbenzene (∼0.02, 5). The mobilities reflect migration retarding influences of the aromatic ring and molecular asymmetry, and a slight ring-shielding effect of methyl groups that tends to enhance the mobility.

Electron Mobilities and Ranges in Liquid Hydrocarbons: Cyclic and Polycyclic, Saturated and Unsaturated Compounds

“…The results are listed in Table 2. The yields in benzene are in good agreement with those reported earlier from this laboratory (17). However, it is probably worth repeating that yields from this I I laboratory (4,8,17) are usually larger by a factor of 1.4 f 0.2 than those reported by Schmidt and Allen (1, 6).…”

“…4. The mobilities in benzene obtained in the present work were on the average 7% higher than those reported earlier from this laboratory (17).…”

Electron transport in o- and m-xylene under high pressure

“…15 Our results for o-xylene at 0.1 MPa, ϭ0.0192 cm 2 /V s at 25°C and an activation energy of 0.203 eV are in good agreement with their results. Our results for m-xylene, at 0.1 MPa: ϭ0.0794 cm 2 /V s at 21°C and 0.139 eV, are somewhat different from ϭ0.057 cm 2 /V s at 19°C and E a ϭ0.19 eV that they reported.…”

Mass spectra and photoelectron spectroscopy of negatively charged benzene clusters, (benzene)n− (n=53–124)

“…On the other hand, the mobility of excess electrons in neat liquid benzene has been investigated as a part of electron transport studies in liquid hydrocarbons. 8 The temperature dependence of the mobility indicated the relatively large activation energy for an electron migration as well as the low electron mobility in this liquid. 8 These results rationalized that the excess electron in liquid benzene is in the localized state and the weak collective trapping occurs in this liquid.…”