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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:59 |
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Conference: Bucharest University Faculty of Physics 2022 Meeting
Section: Atomic and Molecular Physics. Astrophysics. Applications
Title:
Energies and Dipole Interactions of the Dynamic Endo-Exohedral Dodecahedrane complex He@C20H18-Be2C2O
Authors:
Rada-Mihaela COSINSCHI, Alina-Mihaela MUNTEANU, Leonard-Constantin GEBAC
*
Affiliation:
University of Bucharest, Faculty of Physics, Department of Structure of Matter, Earth and Atmosphere Physics, Astrophysics, 405 Atomistilor Street, Magurele, Ilfov
E-mail
rada.cosinschi@s.unibuc.ro
Keywords:
ab-initio, molecular dynamics, dodecahedrane, dipole moment, frequency spectrum, energy transfer
Abstract:
The discovery of fullerenes, carbon-based molecules that take the form of cage- or tube-like structures, represented a great feat of the 20th century, with applications ranging from nanoscience to medicine and various industries. Fullerenes can be used by themselves for their structural or spectroscopic properties, but their capability of hosting other atomic or molecular species within their cavities is of most interest. The object of this paper is the behavioural study of a fullerene-derivate complex, consisting of a moving helium atom, encapsulated within a dodecahedrane cage radical (He@C20H18) that is covalently bonded to the exohedral group -Be2C2O. This extension aligns linearly with the sphere-like structure, defining an axis and a plane of symmetry, that will be referenced to impose “parallel”, respectively “perpendicular” velocities of the He atom in molecular dynamics simulations, starting from the equilibrium position, near the centre of the cage. Computational calculations are conducted using an ab-initio method, the Hartree-Fock approximation, operated on the minimal STO-3G basis set, in order to determine how this system would evolve in time. It has been observed that the dipole moment is affected in different ways by the direction and the magnitude of the velocity: the dipolar amplitude would reach much higher values when the movement is parallel to the main axis, than that from perpendicular movement, phenomenon best observed at low kinetic energies. There is little correlation between the dipole variation and the spatial position. The dipole spectrum of frequencies, on the other hand, will become richer the higher the velocity, indicating an increase in the number of molecular vibrational modes. Furthermore, the kinetic energy of the helium atom decays much faster for greater velocities, a significant energy transfer that manifests as slight deformations in the array of other atoms and translational, respectively, rotational movement of the whole system.
References:
Levine, I.N., Busch, D.H. and Shull, H., 2009. Quantum chemistry (Vol. 6). Upper Saddle River, NJ: Pearson Prentice Hall.
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