A novel neutral nickel complex molecule with the extended TTF dithiolato ligand, propylenedithiotetrathiafulvalenedithiolate [ptdt2- = (S8C9H6)2-], was synthesized. In the [Ni(ptdt)2] crystal. [Ni(ptdt)2] molecules form one-dimensional columns along the a axis, having short intermolecular transverse S···S contacts. The crystal exhibited an extremely high electrical conductivity (7 S cm-1) at room temperature as a neutral molecular crystal. High-pressure resistivity measurements were made up to 72 kbar, which revealed that the resistivity could not be suppressed by applying high pressure unlike the usual highly conducting low-dimensional organic conductors. The tight-binding band structure calculation indicated that the HOMO (highest occupied molecular orbital) and the LUMO (lowest unoccupied molecular orbital) formed “crossing bands”, whose Fermi surfaces tended to vanish due to the HOMO-LUMO interactions. Only very small electron and hole pockets appeared in the Fermi surface due to the transverse interactions between neighboring columns. On the basis of these analyses, the requirements for the development of molecular metals composed of single molecules are discussed.

We prove the existence and the asymptotic completeness of the Dollardtype modified wave operators for many-particle Stark Hamiltonians with long-range potentials.

No abstract

Articles you may be interested inHigh-velocity estimates and inverse scattering for quantum N-body systems with Stark effect Based on the Enss-Weder ͓"The geometrical approach to multidimensional inverse scattering," J. Math. Phys. 36, 3902-3921 ͑1995͔͒ time-dependent method, we study one of multidimensional inverse scattering problems for Stark Hamiltonians. We first show that when the space dimension is greater than or equal to 2, the high velocity limit of the scattering operator determines uniquely the potential such as ͉x͉ −␥ with ␥ Ͼ 1 / 2 which is short range under the Stark effect. This is an improvement of previous results obtained by Nicoleau ͓"Inverse scattering for Stark Hamiltonians with short-range potentials," Asymptotic Anal. 35, 349-359 ͑2003͔͒ and Weder ͓"Multidimensional inverse scattering in an electric field," J. Funct. Anal. 139, 441-465 ͑1996͔͒. Moreover, we prove that for a given long-range part of the potential under the Stark effect, the high velocity limit of the Dollard-type modified scattering operator determines uniquely the short-range part of the potential.