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تسجيل مستخدم جديدElectrodynamical forbiddance of a strong quadrupole light-molecule interaction in fullerene C60 and its withdrawal in fullerene C70
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It is demonstrated that in fullerene C70 which can be considered as a deformed fullerene C60 in some sense there is a withdrawal of an electrodynamical forbiddance of a strong quadrupole light-molecule interaction which is realized in the fullerene C60. This situation occurs because of the reduction of symmetry of C60 from the icosahedral symmetry group Yh to the group D5h. The withdrawal results in appearance of the lines in the SERS spectra of C70 which are forbidden in usual Raman scattering and are allowed in infrared absorption while such lines are forbidden in the SERS spectrum of the fullerene C60 due to the electrodynamical forbiddance. The measured SERS spectra of C70 demonstrates existence of such lines that strongly confirms our ideas about the dipole quadrupole SERS mechanism.
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It is demonstrated that the forbidden lines, which must be present in the SERS, TERS and SEIRA spectra of molecules with sufficiently high symmetry, associated with a strong quadrupole light-molecule interaction, are absent in the fullerene C60. This
result is an experimental manifestation of an electrodynamical forbiddance of the strong quadrupole light-molecule interaction, which must be not only in molecules with cubic symmetry groups, but in the fullerene C60 also.
We analyze using Poisson equation the spatial distributions of the positive charge of carbon atomic nuclei shell and negative charge of electron clouds forming the electrostatic potential of the C60 fullerene shell as a whole. We consider also the ca
se when an extra positive charge appears inside C60 in course of e.g. photoionization of an endohedral A@C. We demonstrate that frequently used radial square-well potential U(r) simulating the C60 shell leads to nonphysical charge densities of the shell in both cases - without and with an extra positive charge inside. We conclude that the square well U(r) modified by adding a Coulomb-potential-like term does not describe the interior polarization of the shell by the electric charge located in the center of the C60 shell. We suggest another model potential, namely that of hyperbolic cosine shape with properly adjusted parameters that is able to describe the monopole polarization of C60 shell. As a concrete illustration, we have calculated the photoionization cross-sections of H@C60 taking into account the monopole polarization of the shell in the frame of suggested model. We demonstrate that proper account of this polarization does not change the photoionization cross-section.
The interactions between atoms and molecules may be described by a potential energy function of the nuclear coordinates. Non-bonded interactions are dominated by repulsive forces at short range and attractive dispersion forces at long range. Experime
ntal data on the detailed interaction potentials for non-bonded interatomic and intermolecular forces is scarce. Here we use terahertz spectroscopy and inelastic neutron scattering to determine the potential energy function for the non-bonded interaction between single He atoms and encapsulating C60 fullerene cages, in the helium endofullerenes 3He and 4He, synthesised by molecular surgery techniques. The experimentally derived potential is compared to estimates from quantum chemistry calculations, and from sums of empirical two-body potentials.
It had been understood that astronomically observed infrared spectrum of carbon rich planetary nebula as like Tc 1 and Lin 49 comes from fullerene (C60). Also, it is well known that graphene is a raw material for synthesizing fullerene. This study se
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The half-life of 7Be implanted in a C60 pellet and gold foil has been measured to be about the same within about 0.2%. Using a radiochemical technique, we also measured that the probability of formation of endohedral 7Be@C60 by nuclear implantation t
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