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Title: Excitations, optical absorption spectra, and optical excitonic gaps of heterofullerenes: I. C60, C59N+ and C48N12

Abstract

Low-energy excitations and optical absorption spectrum of C{sub 60} are computed by using time-dependent (TD) Hartree-Fock (HF), TD-density functional theory (TD-DFT), TD-DFT-based tight-binding (TD-DFT-TB) and a semiempirical ZINDO method. A detailed comparison of experiment and theory for the excitation energies, optical gap and absorption spectrum of C{sub 60} is presented. It is found that electron correlations and collective effects of exciton pairs play important roles in assigning accurately the spectral features of C{sub 60} and the TD-DFT method with non-hybrid functionals or a local spin density approximation leads to more accurate excitation energies than with hybrid functionals. The level of agreement between theory and experiment for C{sub 60} justifies similar calculations of the excitations and optical absorption spectrum of a monomeric azafullerene cation C{sub 59}N{sup +} exhibits distinguishing spectral features different from C{sub 60}: (1) the first singlet is dipole-allowed and the optical gap is redshifted by 1.44 eV; (2) several weaker absorption maxima occur in the visible region; (3) the transient triplet-triplet absorption at 1.60 eV (775 nm) is much broader and the decay of the triplet state is much faster. The calculated spectra of C{sub 59}N{sup +} characterize and explain well our measured ultraviolet-visible (UV-vis) and transient absorptionmore » spectra of the carborane anion salt [C{sub 59}N][Ag(CB{sub 11}H{sub 6}Cl{sub 6}){sub 2}]. For the most stable isomer of C{sub 48}N{sub 12}, we predict that the first singlet is dipole-allowed, the optical gap is redshifted by 1.22 eV relative to that of C{sub 60}, and optical absorption maxima occur at 585, 528, 443, 363, 340, 314 and 303 nm. We point out that the characterization of the UV-vis and transient absorption spectra of C{sub 48}N{sub 12} isomers is helpful in distinguishing the isomer structures required for applications in molecular electronics. For C{sub 59}N{sup +} and C{sub 48}N{sub 12} as well as C{sub 60}, the TD-DFT-TB yields reasonable agreement with TD-DFT calculations at a highly reduced cost. Our study suggests that C{sub 60}, C{sub 59}N{sup +} and C{sub 48}N{sub 12}, which differ in their optical gaps, may have potential applications in polymer science, biology and medicine as single-molecule fluorescent probes.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
15013727
Report Number(s):
UCRL-JRNL-200174
Journal ID: ISSN 0021-9606; JCPSA6; TRN: US200803%%729
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 120; Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; ABSORPTION; ABSORPTION SPECTRA; ELECTRON CORRELATION; SPECTRA; EXCITONS

Citation Formats

Xie, R, Bryant, G W, Sun, G, C Nicklaus, M, Heringer, D, Frauenheim, T, Manaa, M R, Smith, Jr., V H, Araki, Y, and Ito, O. Excitations, optical absorption spectra, and optical excitonic gaps of heterofullerenes: I. C60, C59N+ and C48N12. United States: N. p., 2003. Web.
Xie, R, Bryant, G W, Sun, G, C Nicklaus, M, Heringer, D, Frauenheim, T, Manaa, M R, Smith, Jr., V H, Araki, Y, & Ito, O. Excitations, optical absorption spectra, and optical excitonic gaps of heterofullerenes: I. C60, C59N+ and C48N12. United States.
Xie, R, Bryant, G W, Sun, G, C Nicklaus, M, Heringer, D, Frauenheim, T, Manaa, M R, Smith, Jr., V H, Araki, Y, and Ito, O. 2003. "Excitations, optical absorption spectra, and optical excitonic gaps of heterofullerenes: I. C60, C59N+ and C48N12". United States. https://www.osti.gov/servlets/purl/15013727.
@article{osti_15013727,
title = {Excitations, optical absorption spectra, and optical excitonic gaps of heterofullerenes: I. C60, C59N+ and C48N12},
author = {Xie, R and Bryant, G W and Sun, G and C Nicklaus, M and Heringer, D and Frauenheim, T and Manaa, M R and Smith, Jr., V H and Araki, Y and Ito, O},
abstractNote = {Low-energy excitations and optical absorption spectrum of C{sub 60} are computed by using time-dependent (TD) Hartree-Fock (HF), TD-density functional theory (TD-DFT), TD-DFT-based tight-binding (TD-DFT-TB) and a semiempirical ZINDO method. A detailed comparison of experiment and theory for the excitation energies, optical gap and absorption spectrum of C{sub 60} is presented. It is found that electron correlations and collective effects of exciton pairs play important roles in assigning accurately the spectral features of C{sub 60} and the TD-DFT method with non-hybrid functionals or a local spin density approximation leads to more accurate excitation energies than with hybrid functionals. The level of agreement between theory and experiment for C{sub 60} justifies similar calculations of the excitations and optical absorption spectrum of a monomeric azafullerene cation C{sub 59}N{sup +} exhibits distinguishing spectral features different from C{sub 60}: (1) the first singlet is dipole-allowed and the optical gap is redshifted by 1.44 eV; (2) several weaker absorption maxima occur in the visible region; (3) the transient triplet-triplet absorption at 1.60 eV (775 nm) is much broader and the decay of the triplet state is much faster. The calculated spectra of C{sub 59}N{sup +} characterize and explain well our measured ultraviolet-visible (UV-vis) and transient absorption spectra of the carborane anion salt [C{sub 59}N][Ag(CB{sub 11}H{sub 6}Cl{sub 6}){sub 2}]. For the most stable isomer of C{sub 48}N{sub 12}, we predict that the first singlet is dipole-allowed, the optical gap is redshifted by 1.22 eV relative to that of C{sub 60}, and optical absorption maxima occur at 585, 528, 443, 363, 340, 314 and 303 nm. We point out that the characterization of the UV-vis and transient absorption spectra of C{sub 48}N{sub 12} isomers is helpful in distinguishing the isomer structures required for applications in molecular electronics. For C{sub 59}N{sup +} and C{sub 48}N{sub 12} as well as C{sub 60}, the TD-DFT-TB yields reasonable agreement with TD-DFT calculations at a highly reduced cost. Our study suggests that C{sub 60}, C{sub 59}N{sup +} and C{sub 48}N{sub 12}, which differ in their optical gaps, may have potential applications in polymer science, biology and medicine as single-molecule fluorescent probes.},
doi = {},
url = {https://www.osti.gov/biblio/15013727}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = ,
volume = 120,
place = {United States},
year = {Thu Oct 02 00:00:00 EDT 2003},
month = {Thu Oct 02 00:00:00 EDT 2003}
}