Rotational States of NH^+_4 in Dilute Solution in Alkali Halide Lattices. I. Inelastic Neutron Scattering Studies

概要

論文の詳細を見る
Rotational tunneling and torsional energy states of the NHJ ion in several alkalihalide lattices (KCI, KBr, Kl, Rbl and Csl) have been clnaracterized in theenergy range 0<e<42 men. The most detailed spectra are obtained for thespecimen KBr/NH.Br (0.5 mole's) at low energies (e<2 meV) and in the tem-perature region 1.5<7'<30 K.The results are consistent with a model of energy states for a tetrahedron inan octahedral field.An investigation of the ratios of the intensities of neutron energy loss and energygain peaks in the spectra for I<Br/NH.Br (0.5 /) leads to the conclusion thatconversion between the nuclear spin symmetry species of NU.' occurs with acharacteristic time of several hours. This is in general agreement with the findingsof NMR measurements on the same specimen that arc described in the followingpaper. Moreover, the heat capacity results display a non-lattice contributionwhich is much less than that which would correspond to rapid spin conversion.On the other hand, the intensity ratios for the neutron spectra of two specimensprepared by evaporation of aqueous solutions (Kl/NH.I (2.3 %) and Rbl/NH,(I(2.9 3)) suggest that conversion is more facile in them.
社団法人日本物理学会の論文
1983-07-15