Ab initio calculations are performed for the X̃2E′′ 1 and à 2A′′ 2 states of the cyclopentadienyl radical. An important goal of these calculations is to guide the analysis of the experimentally observed Ã2A′′ 2 -X̃ 2E′′ 1 electronic spectrum. Vibrational frequencies for both the X̃ and à state are reported. Large changes

The laser excited, jet-cooled Ã2A′′ 2 − X̃2E′′ 1 electronic spectrum of the cyclopentadienyl radical yields detailed information about the vibronic structure of both its à and X̃ states. A straight-forward assignment of the à vibronic structure is presented. The X̃ state vibronic structure reveals a comprehensive picture of the Jahn-Teller distortion of its potential energy surface. The molecular ...

We show that complex Lie algebras (in particular sl(2,C)) provide us with an elegant method for studying the transition from real to complex eigenvalues of a class of non-Hermitian Hamiltonians: complexified Scarf II, generalized Pöschl-Teller, and Morse. The characterizations of these Hamiltonians under the so-called pseudoHermiticity are also discussed. PACS: 02.20.Sv; 03.65.Fd; 03.65.Ge

A general formalism for constructing configuration localized states for one-dimensional potentials is presented. It allows the evaluation of accurate approximations to the vibrational matrix elements of the momentum operator and of arbitrary functions of the coordinate. The formalism is applied to three potentials of interest in molecular physics: the harmonic oscillator, Morse, and Pöschl-Tell...

On the basis of the optical and dielectric investigations of [(CH3)2NH2]5Cd2CuCl11 solid solutions the existence of phase transitions at T1 = 175 K and T2 = 117.5 K was confirmed. Both phase transitions were found to be shifted toward lower temperatures with respect to the corresponding transitions in the “host” [(CH3)2NH2]5Cd3Cl11 crystals. It was found that the proton conductivity in [(CH3)2N...

Interplay between the vibronic and spin-orbit coupling in the ͑⌫ 8 + ⌫ 9 ͒ ϫ ͑g +2h͒ Jahn-Teller problem, where ⌫ 8 and ⌫ 9 are the quartet and sextet spin representation, and g and h denote the fourfold and fivefold degenerate vibrational modes in icosahedral symmetry, respectively, is studied. A 4d 9 or 5d 9 transition-metal ion in an icosahedral field may provide a realization of this system.

Competing Jahn-Teller distortions combined with geometrical frustration give rise to a rich phase diagram as a function of x(Cu) and temperature in the spinel system Ni1xCuxCr2O4. The Jahn-Teller distortion of the end members acts in opposite ways with an elongation of the NiO4 tetrahedra resulting in a structural transition at TS1 = 317 K in NiCr2O4, but a flattening in the CuO4 tetrahedra at...

X-ray-absorption fine-structure measurements from the Mn and La K edges of samples of La12xCaxMnO3 (x50→1) are presented as a function of temperature. In the insulating state, distortions of the Mn-O environment are found to be linear with calcium concentration x . These distortions are consistent with a model where individual Mn sites have strong Jahn-Teller ~JT! distortions while Mn sites do ...