Infrared spectra of a K4C60 single-phase thin film have been measured between room temperature and 20 K. At low temperatures, the two high-frequency T1u modes appear as triplets, indicating a static D2h crystal-field stabilized Jahn-Teller distortion of the C60 42 anions. The T1u(4) mode changes into a known doublet above 250 K, a pattern which could have three origins: a dynamic Jahn-Teller ef...

Single crystalline Bi1−xCaxMnO3 (0.74 ≤ x ≤ 0.82) were studied with neutron scattering, electron diffraction and bulk magnetic measurement. We discovered dynamic ferromagnetic spin correlations at high temperatures, which are replaced by antiferromagnetic spin fluctuations at a concomitant charge ordering and structural transition. Our results indicate that thermal-activated hopping of the Jahn...

Recent experiments on single-molecule transistors made of cobalt complexes exhibited anomalously weak gate voltage dependence of the Kondo temperature accompanied by a strong asymmetry in the Coulomb blockade peaks. We show that these observations can both be explained by strong electron–vibron interactions when including anharmonicities of the molecular potential surfaces. The strong electron–...

111 sitzr measurements of the Ni and Co K-edge XAFS spectra of Li1.~Ni02 and Lil.,CoOz as a function of x were successfully carried out for the first time using an electrocl~emical ceii. It is observed that a local Jahn-Teller distortion of the Ni06 octahedron in LiN102 was reduced with deintercalation of Li which caused oxidatiou of the Jahn-Teller d7 ~ i ~ * ion to do Ni4+i011. A substitution...

The solution of the T—t fundamental combinatorial problem is given in a purely analytic form as a sum over binomials. This simplifies other calculations considerably. For an illustration the moments of the optical absorption line shape in the strong coupling limit are derived in a closed form. Furtheron, the optical zero phonon line is calculated. An application to a T — t phase transition chai...

The optical properties of Nd0.7Sr0.3MnO3 thin films have been studied from 5 meV to 25 meV and from 0.25 eV to 3 eV, at temperatures from 15 K to 300 K and magnetic fields up to 8.9 T. A large transfer of spectral weight from high energy to low energy occurs as the temperature is decreased below 180 K, where the dc resistivity peaks, or as the magnetic field is increased. The optical data are f...

The fast computation of the Gauss hypergeometric function 2F1 with all its parameters complex is a difficult task. Although the 2F1 function verifies numerous analytical properties involving power series expansions whose implementation is apparently immediate, their use is thwarted by instabilities induced by cancellations between very large terms. Furthermore, small areas of the complex plane,...

Juan Salafranca,1,2 Rong Yu,3 and Elbio Dagotto1,2 1Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA 2Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 32831, USA 3Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA Received 6 May 2010; revised manuscript received 26 May 2010; p...

The g value of the excited state associated with the GR1 line is analysed in terms of the Coulson-Kearsley defect-molecule model for the vacancy in diamond. It is shown that the experimentally observed g value is entirely consistent with the expected ’T, level of the model provided quenching by the dynamic Jahn-Teller effect is considered. This quenching is estimated from stress splitting data ...

We report recent developments in the theory of dissociative recombination of the H3 ion. The theory is able to explain the surprisingly large dissociative recombination rate observed in storage-ring experiments. We have found that the high rate is caused by Jahn-Teller coupling between the electronic and vibrational degrees of freedom. We compare two theoretical models: A simplified model and a...