Measurement of heavy-hole spin dephasing in (InGa)As quantum dots

We measure the spin dephasing of holes localized in self-assembled (InGa)As quantum dots by spin noise spectroscopy. The localized holes show a distinct hyperfine interaction with the nuclear spin bath despite the p-type symmetry of the valence band states. The experiments reveal a short spin relaxation time {\tau}_{fast}^{hh} of 27 ns and a second, long spin relaxation time {\tau}_{slow}^{hh} which exceeds the latter by more than one order of magnitude. The two times are attributed to heavy hole spins aligned perpendicular and parallel to the stochastic nuclear magnetic field. Intensity dependent measurements and numerical simulations reveal that the long relaxation time is still obscured by light absorption, despite low laser intensity and large detuning. Off-resonant light absorption causes a suppression of the spin noise signal due to the creation of a second hole entailing a vanishing hole spin polarization.Comment: accepted to be published in AP

Hydrogen bonding in infinite hydrogen fluoride and hydrogen chloride chains

Hydrogen bonding in infinite HF and HCl bent (zigzag) chains is studied using the ab initio coupled-cluster singles and doubles (CCSD) correlation method. The correlation contribution to the binding energy is decomposed in terms of nonadditive many-body interactions between the monomers in the chains, the so-called energy increments. Van der Waals constants for the two-body dispersion interaction between distant monomers in the infinite chains are extracted from this decomposition. They allow a partitioning of the correlation contribution to the binding energy into short- and long-range terms. This finding affords a significant reduction in the computational effort of ab initio calculations for solids as only the short-range part requires a sophisticated treatment whereas the long-range part can be summed immediately to infinite distances.Comment: 9 pages, 4 figures, 3 tables, RevTeX4, corrected typo

Calibration of Local Volatility Model with Stochastic Interest Rates by Efficient Numerical PDE Method

Long maturity options or a wide class of hybrid products are evaluated using a local volatility type modelling for the asset price S(t) with a stochastic interest rate r(t). The calibration of the local volatility function is usually time-consuming because of the multi-dimensional nature of the problem. In this paper, we develop a calibration technique based on a partial differential equation (PDE) approach which allows an efficient implementation. The essential idea is based on solving the derived forward equation satisfied by P(t; S; r)Z(t; S; r), where P(t; S; r) represents the risk neutral probability density of (S(t); r(t)) and Z(t; S; r) the projection of the stochastic discounting factor in the state variables (S(t); r(t)). The solution provides effective and sufficient information for the calibration and pricing. The PDE solver is constructed by using ADI (Alternative Direction Implicit) method based on an extension of the Peaceman-Rachford scheme. Furthermore, an efficient algorithm to compute all the corrective terms in the local volatility function due to the stochastic interest rates is proposed by using the PDE solutions and grid points. Different numerical experiments are examined and compared to demonstrate the results of our theoretical analysis

The Nature Of The Chemical Bond In Di- And Polynuclear Metal Cluster Complexes As Depicted By The Analysis Of The Electron Localization Function

The bonding in transition metal complexes is usually rationalized based on molecular orbital schemes. Topological approaches such as the atoms in molecules (AIM) theory or the electron localization function (ELF) analysis provides an alternative interpretation of the bonding relying on a local description. These topological theories give a very convenient framework to achieve the partition of the molecular space in regions with chemical meaning such as atoms, bonds and lone pairs. In this work we review the possibility offered by ELF to investigate the bond in di- tri- and tetranuclear metal complexes containing metal-metal bond. In the case of bimetallic complexes with different nominal bond orders of formula M2(formamidinate)4, the metal-metal interaction is associated to a large electron fluctuation between the two metallic cores and interpreted in terms of simple resonance arguments. Such fluctuation between metals can not be invoked for the trinuclear Fe3(CO)12 or the incomplete cuboidal [Mo3S4(PH3)6 Cl3]4+ complexes. The metal-metal interaction in these clusters is mostly characterized by multicenter bonding as is the case for the tetranuclear heterodimetallic cubane-type complexes resulting from the insertion of Cu or Ni into the previous Mo3 S4 complex. © 2005 Académie des sciences. Published by Elsevier SAS. All rights reserved.89-10 SPEC. ISS.14001412Cotton, F.A., (1993) Multiple Bonds Between Metal Atoms, , Oxford, UK: Oxford University Press. second edCotton, F.A., Nocera, D.G., (2000) Acc. Chem. Res., 33, p. 483Gagliardi, L., Roos, B.O., (2003) Inorg. Chem., 42, pp. 1599-1603Bradley, P.M., Smith, L.T., Eglin, J.L., Turro, C., (2003) Inorg. Chem., 42, p. 7360Bader, R.F.W., (1990) A Quantum Theory Atoms in Molecules, , Oxford, UK: Oxford University PressSilvi, B., Savin, A., (1994) Nature, 371, p. 683Fradera, X., Austen, M.A., Bader, R.F.W., (1998) J. Phys. Chem. A, 103, p. 304Cremer, D., Kraka, E., (1984) Angew. Chem. Int. Ed. Engl., 23, p. 67Lewis, G.N., (1919) J. Am. Chem. Soc., 38, p. 762Lewis, G.N., (1966) Valence and the Structure of Atoms and Molecules, , New York: DoverGillespie, R.J., (1972) Molecular Geometry, , London: Van Nostrang ReinholdAslangul, C., Constanciel, R., Daudel, R., Kottis, P., (1972) Aspects of the Localizability of Electrons and Molecules: Loge Theory and Related Methods, , New York: Academic PressDaudel, R., (1971) Aspects De La Chimie Quantique Contemporaine, , Paris: Éd. CNRSBecke, A.D., Edgecombe, K.E., (1990) J. Phys. Chem., 92, p. 5397Silvi, B., (2004) Phys. Chem. Chem. Phys., 6, p. 256Silvi, B., (2003) J. Phys. Chem. A, 107, p. 3081Savin, A., Silvi, B., Colonna, F., (1996) Can. J. Chem., 74, p. 1088Cotton, F.A., (1965) Inorg. Chem., 4, p. 334Cotton, F.A., Feng, X., (1997) J. Am. Chem. Soc., 119, p. 7514Llusar, R., Beltrán, A., Andrés, J., Fuster, F., Silvi, B., (2001) J. Phys. Chem. A, 105, p. 9460Wang, S.G., Schwarz, W.H.E., (1998) J. Chem. Phys., 109, p. 7252Savin, A., Nesper, R., Wengert, S., Fässler, T., (1997) Angew. Chem. Int. Ed. Engl., 36, p. 1808Bianchi, R., Gervasio, G., Marabello, D., (2000) Inorg. Chem., 39, p. 2360Macchi, P., Proserpio, D.M., Sironi, A., (1998) J. Am. Chem. Soc., 120, p. 13429Bianchi, R., Gervasio, G., Marabello, D., (1998) Chem. Commun., 15, p. 1535Llusar, R., Beltrán, A., Andrés, J., Noury, S., Silvi, S., (1999) J. Comput. Chem., 20, p. 1517Silvi, B., Gatti, C., (2000) J. Phys. Chem. A, 104, p. 947Wei, C.H., Dahl, L.F., (1969) J. Am. Chem. Soc., 91, p. 1351Cotton, F.A., Troup, J.M., (1974) J. Am. Chem. Soc., 96, p. 4155Chevreau, H., Martinsky, C., Sevin, A., Minot, C., Silvi, B., (2003) New J. Chem., 27, p. 1049Hunstock, E., Mealli, C., Calhorda, M.J., Reinhold, J., (1999) Inorg. Chem., 38, p. 5053Pilme, J., Silvi, B., Alikhani, M.E., (2003) J. Phys. Chem. A, 107, p. 4506Dewar, M.J.S., (1951) Bull. Soc. Chim., 18Chatt, J., Duncanson, L.A., (1953) J. Am. Chem. Soc., p. 2939Müller, A., Jostes, R., Cotton, F.A., (1980) Angew. Chem. Int. Ed. Engl., 19, p. 875Cotton, F.A., Llusar, R., (1987) Polyhedron, 6, p. 1741Feliz, M., Llusar, R., Andres, J., Berski, S., Silvi, B., (2002) New J. Chem., 26, p. 844Cotton, F.A., Haas, T.E., (1964) Inorg. Chem., 3, p. 10Cotton, F.A., Haas, T.E., (1964) Inorg. Chem., 3, p. 1217Vergamini, P.J., Vahrenkamp, H., Dahl, L.F., (1971) J. Am. Chem. Soc., 93, p. 6327Bursten, B.E., Cotton, F.A., Hall, M.B., Najjar, R.C., (1982) Inorg. Chem., 21, p. 302Jiang, Y., Tang, A., Hoffmann, R., Huang, J., Lu, J., (1985) Organometallics, 4, p. 27Li, J., Liu, C., Lu, J., (1994) Polyhedron, 13, p. 1841Feliz, M., Garriga, J.M., Llusar, R., Uriel, S., Humphrey, M.G., Lucas, N.T., Samoc, M., Luther-Davies, B., (2001) Inorg. Chem., 40, p. 6132Feliz, M., (2003), PhD thesis, Universitat Jaume I, Castelló, SpainBahn, C.S., Tan, A., Harris, S., (1998) Inorg. Chem., 37, p. 2770Llusar, R., Uriel, S., (2003) Eur. J. Inorg. Chem., 7, p. 1271Akashi, H., Uryu, N., Shibahara, T., (1997) Inorg. Chim. Acta, 261, p. 5

Oxygen Atom Transfer Reactions from Mimoun Complexes to Sulfides and Sulfoxides. A Bonding Evolution Theory Analysis

In this research, a comprehensive theoretical investigation has been conducted on oxygen atom transfer (OAT) reactions from Mimoun complexes to sulfides and sulfoxides. the joint use of the electron localization function (ELF) and Thom's catastrophe theory (CT) provides a powerful tool to analyze the evolution of chemical events along a reaction pathway. the progress of the reaction has been monitored by structural stability domains from ELF topology while the changes between them are controlled by turning points derived from CT which reveal that the reaction mechanism can be separated in several steps: first, a rupture of the peroxo O-1-O-2 bond, then a rearrangement of lone pairs of the sulfur atom occurs and subsequently the formation of S-O-1 bond. the OAT process involving the oxidation of sulfides and sulfoxides is found to be an asynchronous process where O-1-O-2 bond breaking and S-O-1 bond formation processes do not occur simultaneously. Nudeophilic/electrophilic characters of both dimethyl sulfide and dimethyl sulfoxide, respectively, are sufficiently described by our results, which hold the key to unprecedented insight into the mapping of electrons that compose the bonds while the bonds change.Generalitat ValencianaSpanish Ministry Ministerio de Economiay CompetitividadSpanish-Brazilian programFundacion Bancaixa-Universitat Jaume I (UJI)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)São Paulo State Univ, Inst Chem, Interdisciplinary Lab Electrochem & Ceram, BR-14800900 Araraquara, BrazilUniv Jaume 1, Dept Quim Fis & Analit, Castellon de La Plana 12071, SpainUniversidade Federal de São Paulo, UNIFESP, Dept Ciencias Exatas & Terra, BR-09913030 Diadema, BrazilUniv Fed Sao Carlos, Dept Chem, Interdisciplinary Lab Electrochem & Ceram, BR-13565905 Sao Carlos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Ciencias Exatas & Terra, BR-09913030 Diadema, BrazilGeneralitat Valenciana: Prometeo/2009/053Spanish Ministry Ministerio de Economiay Competitividad: CTQ-2012-36253-C03-01Spanish-Brazilian program: PHB2009-0065-PCFundacion Bancaixa-Universitat Jaume I (UJI): P1.1B2010-10FAPESP: 2009/01628-8Web of Scienc