Jahn-Teller effects in the fullerene anion<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi mathvariant="normal">C</mml:mi><mml:mn>60</mml:mn><mml:mrow><mml:mn>3</mml:mn><mml:mo>−</mml:mo></mml:mrow></mml:msubsup></mml:math>

Dunn, J L; Li, Huanming

doi:10.1103/physrevb.71.115411

Cited by 18 publications

(10 citation statements)

References 28 publications

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“…According to relation (18), there are two different moments of inertia I 1 = I x = I y = q 2 and I 3 = I z = 4q 2 . The fact that I x = I y and I z = 0 suggests that the rotational degrees of freedom behave similar to a symmetric top 11,13 .…”

Section: − 60mentioning

confidence: 99%

“…Moreover, the approaches don't provide wavefunctions in the intermediate regime, which is precisely the regime of C 60 . There have been various attempts to construct wavefunctions for all coupling regimes on the basis of coherent states and projection techniques 14,15,16,17,18 . The formalisms used were rather involved and led to complicated analytical expressions and multidimensional integrals.…”

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confidence: 99%

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Jahn-Teller effect versus Hund’s rule coupling inC60N−

Wehrli

Sigrist

2007

Phys. Rev. B

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We propose variational states for the ground state and the low-energy collective rotator excitations in negatively charged C N− 60 ions (N = 1 . . . 5). The approach includes the linear electron-phonon coupling and the Coulomb interaction on the same level. The electron-phonon coupling is treated within the effective mode approximation (EMA) which yields the linear t1u ⊗Hg Jahn-Teller problem whereas the Coulomb interaction gives rise to Hund's rule coupling for N = 2, 3, 4. The Hamiltonian has accidental SO(3) symmetry which allows an elegant formulation in terms of angular momenta. Trial states are constructed from coherent states and using projection operators onto angular momentum subspaces which results in good variational states for the complete parameter range. The evaluation of the corresponding energies is to a large extent analytical. We use the approach for a detailed analysis of the competition between Jahn-Teller effect and Hund's rule coupling, which determines the spin state for N = 2, 3, 4. We calculate the low-spin/high-spin gap for N = 2, 3, 4 as a function of the Hund's rule coupling constant J. We find that the experimentally measured gaps suggest a coupling constant in the range J = 60 − 80 meV. Using a finite value for J, we recalculate the ground state energies of the C N− 60 ions and find that the Jahn-Teller energy gain is partly counterbalanced by the Hund's rule coupling. In particular, the ground state energies for N = 2, 3, 4 are almost equal. I. INTRODUCTIONThe t 1u ⊗ H g Jahn-Teller problem, where electrons in a threefold degenerate orbital interact with a fivefold degenerate phonon multiplet, is known since more than 30 years. It first arised for the particular case of p-electrons in a cubic systems which are equally coupled to E g and T 2g vibrational modes 1 . On the level of linear coupling, an equivalent problem arises in negatively charged C N − 60 ions (N = 1 . . . 5). These materials experienced particular interest when superconductivity was observed in alkali-doped A 3 C 60 (A=K,Cs,Rb, for a review see Ref. 2). The neutral C 60 molecule is a closed shell system and highly symmetric. It has icosahedral symmetry which is the largest threedimensional point-group with 1-, 3-, 4-and 5-dimensional irreducible representations (IR) 3 . The lowest unoccupied molecular orbital (LUMO) of C 60 is threefold degenerate and has t 1u symmetry. It couples to two non-degenerate A g phonon modes and eight 5-fold degenerate H g phonon multiplets 4,5 . In the present work we focus on the nontrivial coupling to the H g multiplets. We restrict our attention to linear coupling and approximate the eight H g multiplets by one effective multiplet which gives rise to the linear, single-mode t 1u ⊗ H g Jahn-Teller problem. Furthermore, we will use the fact that the icosahedral IR's t 1u and H g correspond to the L = 1, 2 IR of SO(3) which don't split under the icosahedral symmetry 3 . As a consequence, the linear t 1u ⊗ H g Jahn-Teller problem is equivalent to the problem of p-electrons interac...

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Section: − 60mentioning

confidence: 99%

mentioning

confidence: 99%

Jahn-Teller effect versus Hund’s rule coupling inC60N−

Wehrli

Sigrist

2007

Phys. Rev. B

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“…This is the usual approach for combining interelectron and JT interactions, 1,2 which has been used in a number of previous works. 1,2,[15][16][17][18][19][20]24 Starting from this basis, Hamiltonians can be constructed that incorporate the interelectron interactions by placing different terms at different energies. Additional contributions to the Hamiltonian are then added to incorporate JT interactions within the terms and between coupled terms.…”

Section: A Hamiltonians For P N ⊗ H Systemsmentioning

confidence: 99%

Interplay between Coulomb and Jahn-Teller effects in icosahedral systems with triplet electronic states coupled toh-type vibrations

et al. 2013

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We will consider the role played by electron-vibration and electron-electron interactions, through Jahn-Teller (JT) and Coulomb interactions, respectively, in icosahedral systems in which triplet electronic states are coupled to h g -type vibrations. Starting from the electronic terms that arise from consideration of Coulomb interactions, we introduce JT couplings both within the terms and between nondegenerate terms. We show how the symmetry of the JT distortion can change when extra electrons are added, and give the conditions under which JT distortions can be suppressed entirely when the Coulomb interactions are sufficiently large. The relevance of our results to anions of the fullerene molecule C 60 are briefly discussed, and existing experimental measurements are used to estimate values for the quadratic JT coupling constants for these anions.

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“…Since the molecular nature strongly remains in these materials, thorough understanding of the JT effect of C 60 anions is crucial. Although JT effect, including dynamic one, of C 60 anions has been intensively investigated, it is only past few years that the actual situation of the ground electronic states of

C_{60}^{n -}

molecule (n = 1‐5) has been established with accurate vibronic coupling parameters …”

Section: Introductionmentioning

confidence: 99%

Dynamical Jahn‐Teller effect in the first excited

Huang

Liú

2019

Int J of Quantum Chemistry

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Jahn‐Teller effect of C60 monoanion in the first electronically excited states was theoretically investigated. The orbital vibronic coupling parameters for t1g next lowest unoccupied molecular orbitals were derived from the Kohn‐Sham orbital levels calculated using a frozen phonon approach with both hybrid B3LYP and CAM‐B3LYP functionals, which take long‐range interaction correction into consideration. With these coupling parameters, the vibronic states of first excited C60− were derived by exactly diagonalizing dynamical Jahn‐Teller Hamiltonian. The results showed that dynamical Jahn‐Teller effects are more significant in the first excited C60− than those in the ground electronic states. This work also clarified that CAM‐B3LYP gives results closer to experimental data than B3LYP.

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Jahn-Teller effects in the fullerene anionC603−

Cited by 18 publications

References 28 publications

Jahn-Teller effect versus Hund’s rule coupling inC60N−

Jahn-Teller effect versus Hund’s rule coupling inC60N−

Interplay between Coulomb and Jahn-Teller effects in icosahedral systems with triplet electronic states coupled toh-type vibrations

Dynamical Jahn‐Teller effect in the first excited

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