Articles you may be interested inLow temperature phase properties of water confined in mesoporous silica MCM-41: Thermodynamic and neutron scattering study Effects of nonframework metal cations and phonon scattering mechanisms on the thermal transport properties of polycrystalline zeolite LTA films J. Appl. Phys. 107, 063518 (2010); 10.1063/1.3327419 X-ray diffraction and inelastic neutron scattering study of 1:1 tetramethylpyrazine chloranilic acid complex: temperature, isotope, and pressure effects Elastic, quasielastic, and inelastic neutron-scattering studies on the charge-transfer hexamethylbenzenetetracyanoquinodimethane complex together with the sheet silicate apophyllite KCa 4 Si 8 O 20 ͑F, OH͒ 8H 2 O, are shown here. We show clear trends across these minerals, illustrating the relative influence of hydrogen bonding and cation bonding. For some of these spectra, the bands are clearly separated, permitting a discussion of their assignments. In particular, we can identify librational bands ͑L͒ or librational edge ͑LE͒ and translational ͑cation-water stretch͒ bands ͑C͒, and by elimination can tentatively assign bands as hydrogen-bond stretch bands ͑H͒, as follows ͑frequencies given in meV͒: Natrolite: 13,18 ͑C͒ 26 ͑H͒, 64,68,87 ͑L͒; Apophyllite 17,26 ͑C͒, 35 ͑H͒ 64,79,98 ͑L͒; Scolecite 10 ͑C͒, 22,29,36,41 ͑H͒, 46 ͑LE͒; Wairakite 12 ͑C͒, 30 ͑LE͒; Bikitaite 13 ͑C͒, 22 ͑H͒, 34 ͑LE͒, 70͑L͒. The results are compared with those for ice and are explained in terms of the nearest-neighbor environment of the water molecule.

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The crystal structures of cobalt and nickel acetate tetrahydrate have been determined at room-temperature and liquid-helium temperature by neutron powder diffraction of the fully deuterated salts. Molecular mechanics and ab initio methods based on these structural results have then been used to calculate the rotational potentials experienced by the methyl groups. We have also used inelastic neutron scattering to measure the rotational potential via the rotational tunneling spectrum of the methyl groups, and this has enabled us to compare different methods for the calculation of partial charges in these ionic compounds. Good agreement between the observables and calculations has been obtained for both compounds when ab initio methods are used to recalculate partial charges at every step of the methyl rotation.

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