UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2022-07-01 16:31

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Conference: Bucharest University Faculty of Physics 2019 Meeting


Section: Atomic and Molecular Physics. Astrophysics. Applications


Title:
Endohedral fullerene based on C20


Authors:
Leonard GEBAC, Mircea BERCU


Affiliation:
Faculty of Physics , University of Bucharest


E-mail
leonard.gebac@gmail.com mircea.bercug@gmail.com


Keywords:
endohedral fullerene, atomistic models, vibrations


Abstract:
Fullerene C20 cage-like structure and endohedral fullerene X@C20 (where X stands for H, He, Li and H2) were analyzed in respect to their electronic structure and stability at semi-empirical and ab-initio level of approximation. Associated potential energy of the radial breathing mode (RBM) is calculated considering both harmonic and anharmonic vibrations for imposed icosahedral (Ih) symmetry. D3d symmetry were found to be reached by C20 structure as a result of atoms relaxation starting from Ih symmetry . Normal vibration modes were analyzed in the case of C20 and X@C20 structures using harmonic approximation. The effects of an external electric field ranging between 10E-5 a.u. to 10E-3 a.u on active vibrations in infrared spectrum indicated the specific changing on line amplitude and shifts. They are taken as predictions for potential experiments by means of optical spectroscopy on endohedral fullerene type samples. The results obtained from diagonalized k matrix were compared to those done in the frame of molecular dynamics simulations. Fourier transforming of the time dependency of the distances between central atom and three carbon atoms of the cage belonging to C3h symmetry, reveals that the frequency of oscillations associated to RBM in the molecular dynamics simulation is the same as that observed in the normal vibrations spectrum. This approach gives more facilities on involving electrical field and temperature parameters on building atomistic models for new applications of embedded atoms inside supramolecular cages.


References:

Horst Prinzbach, Nature, vol 407, 2000