Mössbauer Spectra, Hexacoordinate Complexes A series of compounds Na3[Fe(CN)5RNH2] * nH 20 where R = -H, -CH3, -C2H5, n-C3H7, n-C4H9 and -CH2C6H5 and RNH2 = C5H5N have been studied by Mössbauer spectroscopy. Quadrupole splitting (A EQ) values vary in a limited range (0.68-0.80 mm/sec) indicating only small distortions in the octahedral geometry of the compounds with the substitution of various ...

Perfluorinated compounds (PFCs) were detected in sediment core samples collected in Tokyo Bay to reveal their time trends. The core sample deposited during 1950s-2004 was divided into two- to three-year intervals and the concentrations of 24 types of PFCs were determined. Perfluorooctane sulfonate (PFOS) decreased gradually from the early 1990s and its precursor decreased rapidly in the late 19...

The lattice position of 119Sn atoms after EC decays and a proton-reaction was studied in SnSb and SnTe by emission spectroscopy. In Sn1 l9Sb and Sn 1 lgmTe, defect ll9Sn atoms were found in the Sb or Te site of the matrices. The 119Sb recoil atoms after the proton reaction were found only in the Sb site of SnSb, but they were distributed between both the Sn and Te sites of SnTe. The defect stru...

Matrix isolation techniques have been used in conjunction with Mossbauer spectroscopy to study europium atoms and clusters in solid argon. The measured isomer shift for Eu' monomers in argon was -6.1 mms-'. A value of 13 i: 2 lO-'fm* for the change in the mean square radius (A(?)) was calculated from the isomer shifts of Eu' and EuZ+S04. It was observed that the electron density at the lslEu nu...

Relevance of the Mössbauer spectroscopy in the study of harmonically modulated electronic structures i.e. spin-density waves (SDWs) and charge-density waves (CDWs) is presented and discussed. First, the effect of various parameters pertinent to the SDWs and CDWs is outlined on simulated 119Sn spectra and distributions of the hyperfine field and the isomer shift. Next, various examples of the 11...

Approximately 500 Tg of 2-methyl-1,3-butadiene (isoprene) is emitted by deciduous trees each year. Isoprene oxidation in the atmosphere is initiated primarily by addition of hydroxyl radicals (OH) to C4 or C1 in a ratio 0.57 ± 0.03 (1σ) to produce two sets of distinct allylic radicals. Oxygen (O2) adds to these allylic radicals either δ (Z or E depending on whether the allylic radical is cis or...

Mass-independent isotope fractionations driven by differences in volumes and shapes of nuclei (the field shift effect) are known in several elements and are likely to be found in more. All-electron relativistic electronic structure calculations can predict this effect but at present are computationally intensive and limited to modeling small gas phase molecules and clusters. Density functional ...

Collinear laser spectroscopy of the $N=Z=21$ self-conjugate nucleus $^{42}$Sc has been performed at JYFL IGISOL IV facility in order to determine change nuclear mean-square charge radius between $I^{\pi}=0^{+}$ ground state and $I^{\pi}=7^{+}$ isomer via measurement $^{42\mathrm{g},42\mathrm{m}}$Sc shift. New multi-configurational Dirac-Fock calculations for atomic mass shift field factors have...

methyl tetra - 0-methyl- ?-d- glucopyranoside is stereoselectively prepared from tetramethyl-d- glucopyranose by using (mei+nah) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). similarly, methyl tetra-o-methyl-?- d-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (mei+n-buli) i...