Multielement analysis of drinking water: application of direct current argon plasma-atomic emission spectrometry

The assignment of the SpectraSpan 7 DCP-AES system is restricted to the direct simultaneous determination of the major ions Ca, Mg, Na and K in drinking water. Also, it may serve as a rapid screening technique for assessing compliance with the MAC values given in the Guidelines for Canadian Drinking Water Quality for Ba, Ca, Cu, Fe, Mg, Mn, Na, Ni and Zn. However, it does not have the sensitivity for the direct, simultaneous determination of the trace element levels prescribed with the possible exception of Ba, Cu and Mn. Preconcentration is obviously required to obtain reliable data at the low concentrations of elements usually found in drinking water. The SpectraSpan 7 does not seem to offer any significant advantages with respect to the earlier DCP versions.     

Recoil nuclear polarization in muon capture—Effect of target thickness and finite range of nuclear recoils

The effect of target thickness and finite range of nuclear recoils is investigated in the study of average and longitudinal polarizations of recoiling nuclei resulting from the capture of muons by spin zero target nuclei.     

p-Adic arithmetic procedures for exact matrix computations

Computer procedures are described for error-free matrix computations, using thep-adic arithmetic. As an example, the exact solution of a highly ill-conditioned linear system of equations is obtained, by using the Gaussian elimination method.     

The nπ* states of the thiocarbonyl halides: The ā3A ← X̄1A' electronic transition in thiocarbonyl chlorofluoride

The visible absorption spectrum of thiocarbonyl chlorofluoride, C1FCS in the 495-nm region has been observed in the vapour phase under conditions of high resolution and pressure x path-length and has been assigned to the ā³A'' (n, π^*) ← X?¹A' electronic transition. Three of the six fundamental modes have been assigned for the upper electronic state. Prom a fit of the observed levels in v¹_o (the out-of-plane wagging mode) to the eigenvalues obtained from a quadratic-gaussian potential, the barrier to inversion in the ā³A state has been evaluated to be 1622 cm^?1 The electronic effects of replacing a sulphur by an oxygen atom on the height of the barrier to inversion in the nπ^* carbonyl and thiocarbonyl halides have been explored by the CNDO/2 method. The much lower barriers in the thiocarbonyl compounds has been attributed to the sulphur d_xz AO which is not present in the carbonyl compounds. This AO, which has relatively high weight in the LCAOs which form the π^* MO, has the effect of relieving some of the antibonding density which resides on the carbon atom and thereby reduces the barrier to inversion.     

Asymmetry and polarization of the recoil nucleus in the reaction μ−+12C→12B+vμ

Expressions for the resultant polarizations of ¹²B nuclei obtained in the experimental arrangement of Louvain-Saclay collaboration are derived. How these polarizations are related to the average polarization, the longitudinal polarization and the nuclear recoil asymmetry is investigated.     

Metalloporphyrine in polymeren Matrices und in Mizellen. 2. Mitt. Fe-Porphyrine und Co-Porphyrine in Styrol/1-Vinyl-imidazol-Copolymeren

Ohne Zusammenfassung     

Synthesis,X-ray structure,single-crystal EPR and 1H NMR studies of a distorted square planar Cu(salEen)2(ClO4)2 complex in a novel bilayered architecture: salEen = N,N-diethylethylenesalicylidenamine

Single-crystal X-ray structure and spectroscopic characterizations of Cu(salEen)2(ClO4)2, are reported; salEen is a Schiff base condensation product of equimolar amounts of salicylaldehyde and N,N-diethylethylenediamine. The complex crystallizes in a triclinic space group P1 with a = 12.055(4) A, b = 10.652(3) A, c = 12.701(3) A, alpha = 90.54(2) degrees, beta = 94.39(2) degrees, gamma = 91.35(3) degrees, and Z = 2. The coordination geometry around Cu(II) ion is tetrahedrally distorted square planar with salEen coordinating as a neutral bidentate ligand through N and O donor atoms (average Cu-N and Cu-O distances are 2.004 and 1.880 A, respectively). The counterion ClO4- makes H-bonding contacts with the neighboring cation moieties and forms a one-dimensional layered arrangement of the molecules. The pendent, N,N-diethylethylenediamine groups of salEen (from the centrosymmetrically related molecules) in adjacent layers interpenetrate, forming novel bilayered architectures, which are further held together by pi-pi stacking interactions. EPR studies on single crystals, in three mutually orthogonal planes, yield a rhombic g tensor (gx = 2.041(1), gy = 2.073(1), and gz = 2.220(1)) consistent with the distorted square planar geometry of the CuN2O2 moiety. The peak-to-peak line width of the EPR signal exhibits a |3 cos2 theta - 1|4/3 variation, attributable to one-dimensional magnetic exchange behavior of the complex. The analysis suggests that both the dipole-dipole and exchange interactions contribute to the line width. Interestingly, the complex is amenable for both EPR and NMR studies at ambient temperatures. The proton NMR signals are narrow in CD3CN solutions and the HOMO correlation spectroscopy (COSY) studies reveal the 1H connectivities. Nuclear spin lattice relaxation time (T1) measurements, using inversion recovery method, indicate that T1 values for all the protons are remarkably long compared to those of other mononuclear Cu(II) complexes.