Encaged atoms molecules

The discovery of confinement resonances in the photoelectron angular distribution parameters from encaged atoms may shed light [36] on the origin of anomalously high values of the nondipole asymmetry parameters observed in diatomic molecules [62]. Following [36], consider photoionization of an inner subshell of the atom A in a diatomic molecule AB in the gas phase, i.e., with random orientation of the molecular axis relative to the polarization vector of the radiation. The atom B remains neutral in this process and is arbitrarily located on the sphere with its center at the nucleus of the atom A with radius equal to the interatomic distance in this molecule. To the lowest order, the effect of the atom B on the photoionization parameters can be approximated by the introduction of a spherically symmetric potential that represents the atom B smeared over... 

Of importance is the solubility of a gas, B, in a liquid, A. At low concentrations, each gas molecule or atom is completely encaged by molecules or atoms of the liquid. In this dilute solution, the concentration of gas molecules or atoms is proportional to the gas pressure, Pg(B), above the liquid, so that... 

Fig. 15. a) Stereoview, along the c axis, of the encaged conformations of chlorocyclohexane. Dotted line crystallographic twofold axis. For clarity the guest molecules are shown single-positioned. b) Endocyclic torsion angles of chlorocyclohexane in various conformations (a) major observed (b) major calculated, symmetry (c) minor observed (d) minor calculated. The axial Cl atom. is linked to atom C(l). Reproduced with permission from J. Inch Phenom. 3, 335 (1985)... 

La Cg2 was reported in macroscopic quantities (Chai et al. 1991). It was in the same study, where the symbol was introduced to denote that the former atom or molecule is encaged inside the fullerene molecule. These species containing atoms or molecules inside the fullerene cages are called endohedral fullerenes (EFs). The most studied compounds are the so-called endohedral metallofullerenes (EMFs) due to their high abundancy (Akasaka and Nagase 2002). In 1991, the first structural characterization by X-ray diffraction of an EMF was reported (Chai et al. 1991). 

With metal-loaded zeolites, this technique can be used to determine the quantitative distribution of molecules chemisorbed on the metal particles, the nximber of particles in the sample, and, consequently, the average number of atoms per metal particle. It can also be used to determine quantitatively the distribution of several gases simultaneously chemisorbed on these encaged particles and to determine the percentage of metal located inside or outside the zeolite crystallites. 

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