Nicotinamide complex of silver(III) with expanded coordination number

In strongly alkaline media ([OH-] ≥ 0.12 M), nicotinamide (nica) forms a complex with square-planar Ag(OH)4- [nica] ≥ 0.05 M. The complex decomposes in seconds to nicotinamide N-oxide. The correlation of maximum absorbance of the complex with concentrations of nicotinamide and hydroxide requires that the complex is either the five-coordinate Ag(OH)4(H-1nica)2- or the six-coordinate Ag(OH)5(nica)2-. Comparison with the reactions of Ag(OH)4- with nicotinate ion (nic-) and acetamide under similar conditions indicates that nicotinamide coordinates with Ag(OH)4- by the amido group rather than the nitrogen on the pyridine ring or the amido oxygen. Kinetics of the Ag(III)- nica redox reaction are consistent with direct reaction between nicotinamide and uncoordinated Ag(OH4)-. Oxidation takes place at the pyridine ring, yielding nicotinamide N-oxide. Silver(III) is reduced to monovalent silver

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

GW190814: gravitational waves from the coalescence of a 23 solar mass black hole with a 2.6 solar mass compact object

We report the observation of a compact binary coalescence involving a 22.2–24.3 Me black hole and a compact object with a mass of 2.50–2.67 Me (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO’s and Virgo’s third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg2 at a distance of - + 241 45 41 Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with gravitational waves, - + 0.112 0.009 0.008, and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system. The dimensionless spin of the primary black hole is tightly constrained to �0.07. Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence. We estimate a merger rate density of 1–23 Gpc−3 yr−1 for the new class of binary coalescence sources that GW190814 represents. Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters. However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries

Mössbauer Studies And Electronic Structure Of γ′-fe4n

This paper presents a Mössbauer study of isomer shift, hyperfine field and electric field gradient for γ′-Fe4N. These data are analyzed with the aid of an ab-initio electronic structure calculation using the self-consistent (LMTO) method. The calculated isomer shift and hyperfine field are in good agreement with the experimental results. The present analysis sheds some light into the relevance of previous models for the electronic structure of this system. © 1992.1111-295104Juza, (1966) Advances in Inorganic Chemistry and Radiochemistry, 9, p. 81. , H.J. Emeleus, A.G. Sharpe, Academic Press, New YorkFrazer, (1958) Phys. Rev., 112, p. 751Nagakura, (1968) J. Phys. Soc. Jpn., 25, p. 468Jack, The iron–nitrogen system: the crystal structures of ε-phase iron nitrides (1951) Acta Crystallographica, 5, p. 404Shirane, Takei, Ruby, (1962) Phys. Rev., 126, p. 49Lo, Krishnawamy, Messier, Rao, Mulay, Mössbauer characterization of reactively sputtered iron nitride films (1981) Journal of Vacuum Science and Technology, 18, p. 2Nozik, Wood, Jr., Haacke, (1969) Solid State Commun., 7, p. 1677Suzuki, Sakumoto, Minegismi, Omote, Coercivity and unit particle size of metal pigment (1981) IEEE Transactions on Magnetics, p. 3017Demazeau, Andriamandroso, Pouchard, Tanguy, Hagenmuller, (1983) C.R. Acad. Sci., 297, p. 843Matar, Demazeau, Siberchicot, Magnetic particles derived from iron nitride (1990) IEEE Transactions on Magnetics, p. 60Zener, (1952) Phys. Rev., 85, p. 324Wiener, Berger, (1955) J. Met., 7, p. 360Bilz, (1958) Z. Phys., 153, p. 338Ern, Switendick, (1965) Phys. Rev., 137, p. A1927Lye, Logothetis, (1966) Phys. Rev., 147, p. 622Goodenough, (1960) Phys. Rev., 120, p. 67Andersen, (1975) Phys. Rev. B, 12, p. 3060Andersen, Jepsen, (1977) Physica B, 91, p. 317Skriver, (1984) The LMTO method: Muffin-Tin Orbitals and Electronic Structure, , Springer, New YorkVon Barth, Hedin, (1972) J. Phys. C, 5, p. 1629Matar, Mohn, Demazeau, Siberchicot, The calculated electronic and magnetic structures of Fe4N and Mn 4N (1988) Journal de Physique, 49, p. 1761Clauser, (1970) Solid State Commun., 8, p. 781Greenwood, Gibb, (1971) Mössbauer Spectroscopy, , Chapman and Hall, LondonGutlich, Link, Trautwein, (1978) Mössbauer Spectroscopy and Transition Metal Chemistry, , Springer-Verlag, Berlin/Heidelberg/New YorkRompa, Schuurmans, Williams, (1984) Phys. Rev. Lett., 52, p. 675Jack, Binary and Ternary Interstitial Alloys. II. The Iron-Carbon-Nitrogen System (1948) Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 195, p. 41Pauling, (1940) The Nature of Chemical Bond, , Cornell Univ. Press, Ithaca, NYRundle, A new interpretation of interstitial compounds–metallic carbides, nitrides and oxides of compositionMX (1948) Acta Crystallographica, 1, p. 180Kubler, Williams, Sommers, Formation and coupling of magnetic moments in Heusler alloys (1983) Physical Review B, 28, p. 1745Kuhnen, da Silva, (1987) Phys. Rev. B, 35, p. 370Longworth, (1984) Mössbauer Spectroscopy Applied to Inorganic Chemistry, 1. , G.J. Long, Plenum Press, London, chap. 4Blaha, Schwarz, Herzig, (1985) Phys. Rev. Lett., 54, p. 1192Petrilli, (1989) Ph.D. Thesis, , Universidade de Sao Paulo, BrazilBlaha, Schwarz, Dederichs, (1988) Phys. Rev. B, 37, p. 2792Petrilli, Frota-Pessoa, (1990) J. Phys.: Condens. Matter, 2, p. 135Methfessell, Frota-Pessoa, (1990) J. Phys.: Condens. Matter, 2, p. 14