Quadratic integrals of motions for the systems of identical particles-quantum case

The quantum dynamical systems of identical particles admitting an additional integral quadratic in momenta are considered. It is found that an appropriate ordering procedure exists which allows to convert the classical integrals into their quantum counterparts. The relation to the separation of variables in Schroedinger equation is discussed.Comment: 6 pages, no figure

Site- and orbital-dependent charge donation and spin manipulation in electron-doped metal phthalocyanines

Chemical doping offers promise as a means of tailoring the electrical characteristics of organic molecular compounds. However, unlike for inorganic semiconductors used in electronics applications, controlling the influence of dopants in molecular complexes is complicated by the presence of multiple doping sites, electron acceptor levels, and intramolecular correlation effects. Here we use scanning tunnelling microscopy to analyse the position of individual Li dopants within Cu- and Ni-phthalocyanine molecules in contact with a metal substrate, and probe the charge transfer process with unprecedented spatial resolution. We show that individual phthalocyanine molecules can host at least three distinct stable doping sites and up to six dopant atoms, and that the ligand and metal orbitals can be selectively charged by modifying the configuration of the Li complexes. Li manipulation reveals that charge transfer is determined solely by dopants embedded in the molecules, whereas the magnitude of the conductance gap is sensitive to the molecule-dopant separation. As a result of the strong spin-charge correlation in confined molecular orbitals, alkali atoms provide an effective way for tuning the molecular spin without resorting to magnetic dopants. © 2013 Macmillan Publishers Limited. All rights reserved.This work was supported by the European Research Council (StG 203239 NOMAD), Ministerio de Economía y Competitividad (MAT2010-15659), and Agència de Gestió d'Ajuts Universitaris i de Recerca (2009 SGR 695). A.M. acknlowledges the Spanish Ministerio de Ciencia e Innovación for a Ramon y Cajal Fellowship.Peer Reviewe

Morpholin-4-ium morpholine-4-carbo­dithio­ate

The title compound, C4H10NO+·C5H8NOS2 −, is built up of a morpholinium cation and a dithio­carbamate anion. In the crystal, two structurally independent formula units are linked via N—H⋯S hydrogen bonds, forming an inversion dimer, with graph-set motif R 4 4(12)

Finite-sized Heisenberg chains and magnetism of one-dimensional metal systems

We present a combined experimental and theoretical study of the magnetization of one-dimensional atomic cobalt chains deposited on a platinum surface. We discuss the intrinsic magnetization parameters derived by X-ray magnetic circular dichroism measurements and the observation of ferromagnetic order in one dimension in connection with the presence of strong, dimensionality-dependent anisotropy energy barriers of magnetocrystalline origin. An explicit transfer matrix formalism is developed to treat atomic chains of finite length within the anisotropic Heisenberg model. This model allows us to fit the experimental magnetization curves of cobalt monatomic chains, measured parallel to the easy and hard axes, and provides values of the exchange coupling parameter and the magnetic anisotropy energy consistent with those reported in the literature. The analysis of the spin-spin correlation as a function of temperature provides further insight into the tendency to magnetic order in finite-sized one-dimensional system