The diffraction of electrons by anthracene

Diffuse X-Ray scattering from molecular crystals

“…This led to the theory of two types of thermal diffuse scattering of X-rays by molecular crystals: the extended diffuse bands due to high frequency independent vibrations of the molecules, and the strong diffuse spots observed around Bragg reflections due to low-frequency acoustic waves (see Section 2.2), which obey the Faxe´n-Waller theory (Amoro´s, Canut and De Acha, 1960;Sa´ndor and Wooster, 1963a). Annaka and Amoro´s (1960a) explained the extended diffuse bands observed in the X-ray diffuse scattering from anthracene in terms of independent molecular harmonic vibration (based on the theory developed by Charlesby, Finch and Wilman, 1939) and libration (based on the 'hindered rotator' model of Lipscomb: King and Lipscomb 1950;Atoji, Watanabe´and Lipscomb 1953). Discrepancies between theory and experiment were ascribed to the effect of interaction of molecules.…”

“…Finch, Quarrell and Wilman (1935) first observed extended diffuse bands in transmission electron diffraction photographs from anthracene crystals. The further electron diffraction studies by Charlesby, Finch and Wilman (1939) led to the conclusion that the extended diffuse bands were of thermal origin, due to independent rigid body translational thermal vibrations of the molecules. Similar results were obtained by Annaka and Amoro´s (1960a) for the X-ray diffuse scattering of anthracene.…”

“…The observed intensity distribution was compared to that calculated assuming independent rigid-body vibrations of the anthracene molecules (Sa´ndor and Wooster, 1963b). The theory of Charlesby, Finch and Wilman (1939), extended by Amoro´s (Amoro´s, Canut, and De Acha, 1960;Annaka and Amoro´s, 1960a) for independent isotropic translational molecular vibrations, was generalised to cover anisotropic translational and rotational vibrations, since this was known to be the case from the refinement of the thermal parameters of anthracene from the X-ray structure (Cruickshank, 1956(Cruickshank, ,1957. Discrepancies were ascribed to the neglect of phase relationships between the molecules.…”

Band‐gap Modification in a Nanoscale Region of Polyethylene by Fast Electrons

“…It is known that when irradiated, bulk PE produces hydrogen molecules while scission and cross-linking occurring simultaneously. [30,31] The degree of scission and cross-linking and the yield of the by-product can be estimated by the G value. It is the number of units of the product (here H 2 ) generated per each 100 eV of radiation incident upon the specimen (here PE).…”

Thermolumineszenzuntersuchungen an Polymeren

“…Die Ruckkehr in den Gleichgcwichtszustand miiB fiber eino Energiebarriere erfolgen. 3. Das System mul3 in Verbindung mit cinom Wurmercservoir stelien, das die thermischo Energie zur Aktivierung liefert.…”