The experimental electron density rho(r) of Mn2(CO)10 was determined by a multipole analysis of accurate X-ray diffraction data at 120 K. The quantum theory of atoms in molecules (QTAM) was applied to rho(r) and its Laplacian [symbol: see text] 2 rho(r). The QTAM analysis of rho(r) showed the presence of a bond critical point (rc); its associated bond path connects the two Mn atoms, but no cross interaction line was found between one manganese and the equatorial carbonyls of the other. The distribution of [symbol: see text] 2 rho(r) indicated "closed-shell" interactions for the metallic Mn-Mn bond and the dative Mn-CO bonds. The values of the topological parameters of the density at rc, rho(rc), [symbol: see text] 2 rho(rc), G(rc) (kinetic energy density), and V(rc) (potential energy density), characterize the bonds and are intermediate to those corresponding to typical ionic and covalent bonds.

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A detailed description of the ability of halogen bonding to control recognition, self-organization, and self-assembly in I2 crystal, combining low-temperature X-ray diffraction experiments and theoretical DFT-D and MP2 studies of charge density, is reported. The bond critical point features were analyzed using the bonding ellipsoids, in order to make them more evident and easier to compare. We showed that one-electron potential, in contrast to Laplacian of electron density, allows the electron concentration and depletion regions in the valence shell of the iodine atoms to be revealed. Thus, it was demonstrated as an effective tool for understanding the molecular recognition processes in iodine crystal, describing the mutually complementary areas of concentration and depletion of electron density in adjacent molecules. This finding was also confirmed in terms of electrostatic potential, especially using the concept of σ-hole. The tiny features of the electrostatic component of halogen–halogen interactions were also visualized through the superposition of the gradient fields of electron density and electrostatic potential. The general picture provided significant arguments supporting the distinction between Type-I (van der Waals) and Type-II (Lewis molecular recognition mechanism) I··I interactions. The energies of these interactions, evaluated on the basis of empirical relationships with bond critical points parameters, have allowed estimating the lattice energy for crystalline I2, which has been found in reasonable agreement with the experimental sublimation energy.

The MUNU experiment was carried out at the Bugey nuclear power reactor. The aim was the study of electron antineutrino-electron elastic scattering at low energy. The recoil electrons were recorded in a gas time projection chamber, immersed in a tank filled with liquid scintillator serving as veto detector, suppressing in particular Compton electrons. The measured electron recoil spectrum is presented. Upper limits on the neutrino magnetic moment were derived and are discussed.Comment: 9 pages, 7 figures Added reference: p.3, 1st col., TEXONO Added sentence: p.4, 1st col., electron attachement Modified sentence: p.5, 1st col., readout sequence Added sentence: p.5, 1st col., fast rise time cu