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Title: Contribution of nuclear displacements to the static polarizability of molecules in an external electric field: Application to fluorinated fullerenes C{sub 60}F{sub n}

Abstract

In molecules with ionic contributions to the binding, the contribution of nuclear displacements (due to the external field) to the static polarizability can be decisive. Using the finite field method, we optimized the structure with and without a finite external electric field by a total energy minimization and we calculated the polarizability from the induced dipole moment. In C{sub 60}F{sub n}, fluorination mostly increases the polarizability. Only for n=2 and 18, where the molecule without an external field has a very large dipole moment, does fluorination decrease it. For large n (n=20, 36, and 48), the polarizability per added F atom due to nuclear displacements is increased by a factor of about 2. The validity of the additivity model has been discussed.

Authors:
; ;  [1]
  1. Leibniz Institute for Solid State and Materials Research, IFW Dresden, P.O. Box 270016, 01171 Dresden (Germany)
Publication Date:
OSTI Identifier:
20787324
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevA.73.054501; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOMS; DIPOLE MOMENTS; ELECTRIC FIELDS; FLUORINATION; FULLERENES; MINIMIZATION; MOLECULES; POLARIZABILITY

Citation Formats

Zagorodniy, K., Taut, M., and Hermann, H. Contribution of nuclear displacements to the static polarizability of molecules in an external electric field: Application to fluorinated fullerenes C{sub 60}F{sub n}. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Zagorodniy, K., Taut, M., & Hermann, H. Contribution of nuclear displacements to the static polarizability of molecules in an external electric field: Application to fluorinated fullerenes C{sub 60}F{sub n}. United States. doi:10.1103/PHYSREVA.73.0.
Zagorodniy, K., Taut, M., and Hermann, H. Mon . "Contribution of nuclear displacements to the static polarizability of molecules in an external electric field: Application to fluorinated fullerenes C{sub 60}F{sub n}". United States. doi:10.1103/PHYSREVA.73.0.
@article{osti_20787324,
title = {Contribution of nuclear displacements to the static polarizability of molecules in an external electric field: Application to fluorinated fullerenes C{sub 60}F{sub n}},
author = {Zagorodniy, K. and Taut, M. and Hermann, H.},
abstractNote = {In molecules with ionic contributions to the binding, the contribution of nuclear displacements (due to the external field) to the static polarizability can be decisive. Using the finite field method, we optimized the structure with and without a finite external electric field by a total energy minimization and we calculated the polarizability from the induced dipole moment. In C{sub 60}F{sub n}, fluorination mostly increases the polarizability. Only for n=2 and 18, where the molecule without an external field has a very large dipole moment, does fluorination decrease it. For large n (n=20, 36, and 48), the polarizability per added F atom due to nuclear displacements is increased by a factor of about 2. The validity of the additivity model has been discussed.},
doi = {10.1103/PHYSREVA.73.0},
journal = {Physical Review. A},
number = 5,
volume = 73,
place = {United States},
year = {Mon May 15 00:00:00 EDT 2006},
month = {Mon May 15 00:00:00 EDT 2006}
}
  • To elucidate the structures of C{sub 60}F{sub 36} and C{sub 60}F{sub 48}, X-ray diffraction and electron diffraction experiments have been performed. It was found that the X-ray diffractograms of C{sub 60}F{sub 36} and C{sub 60}F{sub 48} at room temperature are indexed by bcc and bct lattices, respectively. In situ X-ray diffraction experiments at high temperatures have been also undertaken. The bct to fcc phase transition of C{sub 60}Fe{sub 48} was observed. The mechanism of the transition and the stabilities to the structures of fluorinated fullerenes are discussed.
  • Reactions of fullerene C{sub 60} with atomic fluorine are studied by the unrestricted broken spin symmetry Hartree-Fock (UBS HF) approach implemented in semiempirical codes based on the AMI technique. The calculations are focused on a successive addition of a fluorine atom to the fullerene cage following the indication of the highest chemical susceptibility of the cage atom, which is calculated at each step. The proposed computational synthesis is based on the effectively unpaired-electron concept of the chemical susceptibility of fullerene atoms. The obtained results are analyzed from the standpoints of energy, symmetry, and the composition abundance. A good fitting ofmore » the data to experimental findings proves a creative role of the suggested synthetic methodology.« less
  • A photoelectron spectroscopy investigation of the fluorofullerene anions C 60F n - (n = 17, 33, 35, 43, 45, 47) and the doubly-charged anions C 60F 34 2- and C 60F 46 2- is reported. The electron affinities for the corresponding neutral molecules, C 60F n, were directly measured and were found to increase as n increased, reaching the extremely high value of 5.66 ± 0.10 eV for C 60F 47. Density functional calculations suggest that the experimentally observed species C 60F 17 -, C 60F 35 -, and C 60F 47 - were each formed by reductive-defluorination of themore » parent fluorofullerene, C 3v-C 60F 18, C 60F 36 (a mixture of isomers), and D 3-C 60F 48, respectively, without rearrangement of the remaining fluorine atoms. The DFT-predicted stability of C 60F 47 - was verified by its generation by chemical reduction from D 3-C 60F 48 in chloroform solution at 25 °C and its characterization by mass spectrometry and 19F NMR spectroscopy. Further reductive-defluorination of C 60F 47 - in solution resulted in the selective generation of a new fluorofullerene, D 2-C 60F 44, which was also characterized by mass spectrometry and 19F NMR spectroscopy.« less
  • Valence electron contributions to the static molecular third-order polarizabilities ({gamma}) are calculated for C{sub 60}, C{sub 70}, and two stable structures of C{sub 84} (D{sub 2} and D{sub 2d}). The method utilized is based on the finite-field approach coupled with semiempirical polarization calculations on all-valence electrons. An increase in the third-order polarizability contributions is observed for molecular structures with a reduction in group symmetry, in agreement with recent experimental observations for these fullerenes. This increase is attributed mainly to the appearance of aromatic structures within the molecules as well as to the increase in molecular volume. 26 refs., 4 tabs.
  • In this work we discuss limitations in the stability of monosubstituted heterohedral fullerenes. Both quantum and molecular mechanical approaches are used to understand the limits in bonding and structural characteristics of these materials. Both the electronic structure calculations and the molecular mechanics study suggest that greater inherent stability exists in the monosubstituted boron fullerene compared with the equivalent nitrogen analog. This is somewhat consistent with the sparse experimental information provided for N-doped fullerenes. In addition, structural comparisons show significantly greater distortion of the fullerene framework for the nitrogen-substituted material. Electronic structure calculations predict greater disruption of bonding near the substitutionmore » site for C{sub 59}N in comparison with C{sub 59}B, and the energy trends from these calculations suggest that the stability of the C{sub 59}N is considerably lower than that of C{sub 59}B. Furthermore, the electronic structure calculations suggest that C{sub 59}N{sup +} may be more stable than the parent neutral material. Disubstituted heterohedral fullerenes have been analyzed utilizing similar electronic requisites for stability. 25 refs., 5 figs., 5 tabs.« less