Detailed calculations performed on the (NaC1)2-species identify two stable structures, one with an electron bound in the dipole field of a nearly linear NaClNaCl dimer and the other with the electron trapped between two NaCl molecules in a linear arrangement with their dipoles opposed. The cyclic (NaC1)2 dimer is found not to bind an electron. Results for electrons trapped by three and four NaCl molecules are also presented. the National Science Foundation. The calculations were performed on a Harris HlOOO superminicomputer, funded in part with a grant from the National Science Foundation, and on the Cray XMP-48 at the Pittsburgh Supercomputer Center.

Configuration interaction and coupled-cluster calculations are carried out on the low-lying electronic states of Al2, Al2+, and Alf. On the basis of these calculations we conclude that the lowest3 If and 3 " states of Al2 lie within 200 cm"1 11of one another, with the 3 " state being the more stable. Al2+ is predicted to have a 2Sg+ ground state, with a 2nu state lying 0.54 eV higher in energy. Six anion states of Al2 are predicted to be bound, with the ground-state anion being 4If.

A simple, rapid and sensitive spectrophotometric method is described for the determination of hydrogen peroxide using toluidine blue as a reagent. The proposed method is based on the liberation of iodine in acidic medium equivalent to the amount of hydrogen peroxide present. The liberated iodine bleaches the blue color of toluidine blue and is measured at 628 nm. The decrease in absorbance is directly proportional to hydrogen peroxide concentration and obeys Beer's law in the range 0.2 x 10(-6) -14 x 10(-6) mol L(-1). The molar absorptivity, sandel's sensitivity, detection limit and quantitation limit of the method were found to be 1.82 x 10(4) L mol(-1) cm(-1), 2.01 x 10(-9) mol L(-1), 1.41 x 10(-6) mol L(-1) and 4.28 x 10(-6) mol L(-1) respectively. The results of analysis of the proposed method are compared favorably with those from a reference method.

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A detailed study of the electronic structures of a series of d1 transition metal oxohalo complexes (MOXn)m−, where M = V, Nb, Cr, Mo, and W and X = F, Cl, and Br (n = 4 or 5), has been carried out by the SCF–MS–Xα method. The results provide values of the d–d transition energies, and also give some understanding of the similarities and differences in bonding characteristics of the penta- and hexacoordinated complexes, and of the observed trends in the g and metal hyperfine interaction tensors in these series. The utility of the SCF–MS–Xα method in predicting trends in bonding and in ESR parameters in transition metal complexes is discussed and the results compared with those from ab inito methods.