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Secondary Electron Emission from Some Aromatic Hydrocarbons
Author(s) -
Ya. Bubnov L.,
Frankevich E. L.
Publication year - 1974
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220620130
Subject(s) - anthracene , electron , tetracene , intramolecular force , scattering , amorphous solid , chemistry , pyrene , mean free path , atomic physics , materials science , molecular physics , physics , crystallography , optics , photochemistry , organic chemistry , quantum mechanics
Results of the investigation of secondary electron emission from polycrystalline films of tetracene and pyrene and from both amorphous films and single crystals of anthracene are reported. The determination of the relative number of true secondary electrons which lose their initial energy by exciting intramolecular vibrations (≈60%) and excitons (≈40%) has permitted an estimation of ranges of energy loss in these two processes: more than 70 Å in the former and from 50 to 150 Å in the latter process. The former group of electrons is named subexciting electrons. The mean distance covered by the subexciting electron while it still has sufficient energy to excite intramolecular vibrations is estimated to 200 to 500 Å. All these estimates are essentially new as compared to those used at present. Comparison of secondary electron emission coefficients in anthracene single crystals and amorphous films leads to the conclusion that motion of subexciting electrons in the anthracene crystal is not diffuse. Experimentally obtained range of subexciting electrons, as related to angular scattering (greater than 70 Å), is large in comparison with lattice constant and indicates that in contrast to assumptions of the “compressed gas” model in molecular crystals angular scattering is a relatively rare phenomenon.