1,721,099 research outputs found
Low-energy excitations of a linearly Jahn-Teller coupled orbital quintet
No full textThe low-energy spectra of the single-mode h circle times(G+H) linear Jahn-Teller model is studied by means of exact diagonalization. Both eigenenergies and photoemission spectral intensities are computed. These spectra are useful to understand the vibronic dynamics of icosahedral clusters with partly filled orbital quintet molecular shells, for example C-60 positive ions
Introduction to the physics of matter: basic atomic, molecular, and solid-state physics
No full textThis book offers an up-to-date, compact presentation of basic topics in the physics of matter, from atoms to molecules to solids, including elements of statistical mechanics. The adiabatic separation of the motion of electrons and nuclei in matter and its spectroscopic implications are outlined for molecules and recalled regularly in the study of the dynamics of gases and solids. Numerous experiments are described and more than 160 figures give a clear visual impression of the main concepts. Sufficient detail of mathematical derivations is provided to enable students to follow easily. The focus is on present-day understanding and especially on phenomena fitting various independent-particle models. The historical development of this understanding, and phenomena such as magnetism and superconductivity, where interparticle interactions and nonadiabatic effects play a crucial role, are mostly omitted. A final outlook section stimulates the curiosity of the reader to pursue the study of such advanced topics in graduate courses
Jahn-Teller and Coulomb correlations in fullerene ions and compounds : from isolated ions to metal, insulator, and superconductor phases of alkali fulleride solids
No full textWe offer a partial review of some theoretical aspects of the interplay among
strong electron-electron Coulomb plus exchange correlations and Jahn-Teller
vibronic phenomena in fullerene ions and in solid conductors, superconductors, insulators. The first half of this work covers molecular fullerene ions, their intra-molecular Jahn-Teller effect, Coulomb exchange (Hund's rule) interactions, and
molecular vibronic spectroscopies. Several aspects, calculations, and phenomena are discussed also in connection with spectroscopic data. The second part addresses intermolecular electron motion in
molecular solid fullerides, with special emphasis given to trivalent cases such as
K3C60 and NH3 K3C60, where metallic, superconducting and Mott insulating phases are at play. Dynamical mean field theory
approaches to simplified Hamiltonians for this system are discussed in the light of some of the observed phenomenology. In particular NH3 K3C60 and the more recently studied cubic Cs3C60 compounds are discussed as realizations of Mott-Jahn-Teller insulators, which, under pressure, turn into strongly correlated superconductors, sharing several important elements with the cuprate superconductors
Off-diagonal geometric phases
No full textWe investigate the adiabatic evolution of a set of nondegenerate eigenstates of a parametrized Hamiltonian. Their relative phase change can be related to geometric measurable quantities that extend the familiar concept of Berry phase to the evolution of more than one state. We present several physical systems where these concepts can be applied, including an experiment on microwave cavities for which off-diagonal phases can be determined from published data
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