Quantum Monte Carlo Impurity Solver for Cluster DMFT and Electronic Structure Calculations in Adjustable Base

We generalized the recently introduced new impurity solver based on the diagrammatic expansion around the atomic limit and Quantum Monte Carlo summation of the diagrams. We present generalization to the cluster of impurities, which is at the heart of the cluster Dynamical Mean-Field methods, and to realistic multiplet structure of a correlated atom, which will allow a high precision study of actinide and lanthanide based compounds with the combination of the Dynamical Mean-Field theory and band structure methods. The approach is applied to both, the two dimensional Hubbard and t-J model within Cellular Dynamical Mean Field method. The efficient implementation of the new algorithm, which we describe in detail, allows us to study coherence of the system at low temperature from the underdoped to overdoped regime. We show that the point of maximal superconducting transition temperature coincides with the point of maximum scattering rate although this optimal doped point appears at different electron densities in the two models. The power of the method is further demonstrated on the example of the Kondo volume collapse transition in Cerium. The valence histogram of the DMFT solution is presented showing the importance of the multiplet splitting of the atomic states.Comment: 12 pages, 4 figure

Charged particle multiplicity and momenta in e+e−→We^{+}e^{-} \to W-pair decays at 189 GeV

The charged particle multiplicity of W-pair decays is measured with the ALEPH detector at LEP at a cms energy of 189GeV. This is motivated by the study of possible colour reconnection effects in W-pairs where both decay hadronically. The average charged multiplicity of WW>qqqq is compared with predictions of fragmentation models tuned to measurements performed at the Z peak and with measured multiplicities in WW>qqlv events. It is compatible, both with models without implementation of colour reconnection, and with the models including colour reconnection that are studied here

Studies in the chemistry of the nitrogen-halogen bond

The reactions of diraethylchloramine with a variety of different substrates has been studied. With basic substrates such as hydrazine and the alkyl substituted hydrazines, dimethylchloramine acts as an oxidising agent, but with ammonia and the methylamines contrast was found with the corresponding NH(_2)Cl reactions. Simple nucleophillic attack of the amine on the diraethylchloramine nitrogen explains the products found in the reactions with CH(_3)NH(_2) and NH(_3), whilst dehydrohalegonation reaction accounts for the observed products. With dimethylamine a complex reaction occurs which is most probably intimately associated with the decomposition of (CH(_3))(_2)NCl itself. Dimethylchloramine reacts in two different ways with methyl esters of certain acids. On the one hand, esters typified by CH(_3)0S0(_2)F, and including CH(_3)0Cl0(_3), yielding a cationic species identified as (CH(_3))(_3)(^+)NCl. In this cation, the nitrogen chlorine bond possesses a slight dipole, the positive end of which is directed towards the chlorine atom, in accord with the (^36)Cl NQR absorption frequency of 56.09 MHz, found in the Cl0(^-)(_4), (CH(_3))(_3)(^+)3NCl Cl0(^-)(_4), being in excess of that found for Cl2 . The application of standard approximate methods to the observed coupling constants for the CIO4 and BP4 indicate that the bonding between the nitrogen and chlorine atoms in the cation involves an almost pure chlorine p orbital. The ion, (CH(_3))(_3)(^+)NCl, is precipitable from aqueous solutions of the chlorine trimethylaraine complex, (CH(_3))(_3)NCl(_2), by Cl0(^-)(_4) and BF(^-)(_4) ions. With the methyl halides, dimethylchloramme reacts to yield, with methyl bromide, the addition complex of trimethylaraine, (CH3)3NBrCl, the infra red spectrum of which fits well with the trends observed for other (CH3)3N (Halogen)2 addition complexes, whilst with methyl iodide, a novel tetramethylammonium pseudopolyhalide, (CH(_3))(_4)(^+)N[(CH(_3))(_2)N(ICl)(_2)](^-), forms. Dimethyl bromamine, (CH(_3))(_2)NBr, reacts in a similar way to (CH(_3))(_2)NCl, with alkylating agents, the unstable (CH(_3))(_3)(^+)NBr 0S02(_)F(^-) forms with CH(_3)0S0(_2)F and (CH(_3))(_2)NBr Cl0(^-)(_4) can be precipitated from aqueous solutions of the fluorosulphate by Cl0(^-)(_4) ions. With CH(_3)I, (CH(_3))(_2)NBr yields, in a similar way to (CH(_3))(_2)NCl, (CH(_3))(_4)(^4)N[(CH(_3))(_2)N(IBr(_2))](^-)

Alien Registration- Cowan, Lee D. (Blaine, Aroostook County)

https://digitalmaine.com/alien_docs/27365/thumbnail.jp