[en] Coupled cluster, nth-order Moller-Plesset perturbation and quadratic configuration interaction theories are used to calculate the electric field gradients and nuclear quadruple coupling constants of 12 nitrogen-containing molecules using laser sets of valence DZ + P and TZ + P. These molecules are: HCN, HNC, CH₃NC, CF₃NC, NCNC, HCCNC, FCH₂NC, F₂CHNC, CH₃CH₂NC, H₂CCH, NC, and NCCCH₂NC. 52 refs., 4 figs., 5 tabs

[en] A new method is proposed for determining the ages of molecular clouds. The method utilizes the properties of the long-chain organic molecules known as the cyanopolyynes (HC+ 1N, k = 0, l, 2, 3...), which are found in a variety of clouds. The observed regular abundance decline of these molecules as a function of chain length suggests that they are formed sequentially. If so, the age of the cloud can be read off as the time to grow the longest chain present. Although the creation process for the chains is still unknown, the age can be obtained from knowledge of the chain destruction mechanism. Destruction is probably due to adsorption onto the surfaces of interstellar grains. Using the known properties of grains, the age can be obtained from the cloud density and the abundance ratios of the cyanopolyynes. As a first application, I obtain minimum ages for the four dark clouds B335, TMC-1, TMC-2, and Ll83. These minimum ages are l.3 x l0⁶ yr, 9.7 x l0⁵ yr, 3.4 x l0⁵ yr, and 3.3 x l0⁵ yr, respectively. In each case, the ages are greater than or equal to the cloud's free-fall collapse time. These four clouds are therefore either in a state of hydrostatic balance or have only recently begun to collapse, following an earlier period of hydrostatic support

[en] An method for preparing a coordination complex of isonitrile ligand and a radioisotope of Te, Ru, Co, Pt, Re, Os, Ir, W, Re, Cr, Mo, Mn, Ni, Rh, Nb and Ta from a non-radioactive metal adduct of the isonitrile

[en] A method is described for preparing a coordination complex of an isonitrile ligand and a radioactive metal selected from the class consisting of radioactive isotopes of Tc, Ru, Co, Pt, Fe, Os, Ir, W, Re, Cr, Mo, Mn, Ni, Rh, Pd, Nb and Ta. The method comprises preparing a soluble metal adduct of the isonitrile ligand by admixing the ligand with a salt of a displaceable metal having a complete d-electron shell selected from the class consisting of Zn, Ga, Cd, In, Sn, Hg, Tl, Pb and Bi to form a soluble metal-isonitrile salt, and admixing the metal isonitrile salt with a salt comprising the radioactive metal in a suitable solvent to displace the displaceable metal with the radioactive metal thereby forming the coordination complex

No abstract available

[en] Isocyanic acid (HNCO) is a well-known interstellar molecule. Evidence also exists for the presence of two of its metastable isomers in the interstellar medium: HCNO (fulminic acid) and HOCN (cyanic acid). Fulminic acid has been detected toward cold and lukewarm sources, while cyanic acid has been detected both in these sources and in warm sources in the Galactic Center. Gas-phase models can reproduce the abundances of the isomers in cold sources, but overproduce HCNO in the Galactic Center. Here we present a detailed study of a gas-grain model that contains these three isomers, plus a fourth isomer, isofulminic acid (HONC), for four types of sources: hot cores, the warm envelopes of hot cores, lukewarm corinos, and cold cores. The current model is partially able to rationalize the abundances of HNCO, HOCN, and HCNO in cold and warm sources. Predictions for HONC in all environments are also made.

No abstract available

No abstract available

[en] In this paper, a potentiometric sensor based on polyaniline conducting polymer for potentiometric determination of Cr (VI) ions is reported. Polyaniline was synthesized electrochemically (cyclic voltammetry method) onto a micro pencil graphite electrode (0.7 mm diameter) in the presence of HCl and diphenylcarbazide (termed as (PGE/PAni/DPC). Some initial experiments were performed in order to find out the optimized conditions for preparation of the introduced Cr (VI) sensor electrode. The plot of E vs. log [Cr (VI)], showed a linear response in the range from 1.0 x 10^-6 to 1.0 x 10^-1 M. High repeatability with the detection limit of 8.0 x 10^-7 M was obtained

[en] The stability constants of Zn^II, Cd^II and Mn^II with 1-amidino-o-isobutylurea (ABⁱUH) in aqueous medium at different ionic strengths and temperatures using Calvin-Bjerrum technique as modified by Irving and Rossotti are reported. The values of thermodynamic stability constants have been evaluated