TY - JOUR
T1 - Proton magnetic resonance in Sr(NH3)6
T2 - Evidence for rapid ammonia diffusion
AU - White, T. R.
AU - Glaunsinger, W. S.
AU - Gordon, D. A.
AU - Marzke, R. F.
N1 - Funding Information:
The alkaline earth metals Ca, Sr, and Ba dissolve in liquid ammonia and, upon freezing, form metallic compounds having the composition M(NH3)6, where M = Ca, Sr, or Ba [ 11. The .metallic nature of these compounds originates from the loss of up to two electrons for each molecular complex to a conduction band_ Recent experiments have indicated that these solids have urmsual properties and structures. It is expected that the rather large radius of the molecular ions, coupled with Brillouin-zone-contact effects, will result in a low-electron-density metal, and this expectation is supported by electrical transport [24] and magnetic measure--ments [5,6] in metal-ammonia compounds. A recent neutron diffraction study has revealed that Ca(ND& is composed of highly distorted ammonia molecules arranged in an exact octahedron around the Ca atoms, with each ND, molecule having a fourfold rotational disorder [7]. The low-temperature proton magnetic resonance (‘H NMR) linewidth in Ca(NH3)6 is in good agreement with that calculated from the neutron-diffrac-* Research supported by National Science Foundation Grant No. DMR 7509215.
PY - 1978/2/1
Y1 - 1978/2/1
N2 - The proton magnetic resonance linewidth in Sr(NH3)6 has been measured in the range 40-300 K. Two line-narrowing transitions have been detected as the temperature is increased. Between 40 and 54 K the linewidth decreases from about 2 to 1.6 G, and in the range 97-140 K the line narrows from about 1.6 G to 15 mG. The results are interpreted in terms of proton tunneling at low temperatures, a transition from tunneling to classical rotation of ammonia molecules between 40 and 54 K, and an ammonia diffusional transition with an activation energy of about 3 kcal/mole in the range 97-140 K.
AB - The proton magnetic resonance linewidth in Sr(NH3)6 has been measured in the range 40-300 K. Two line-narrowing transitions have been detected as the temperature is increased. Between 40 and 54 K the linewidth decreases from about 2 to 1.6 G, and in the range 97-140 K the line narrows from about 1.6 G to 15 mG. The results are interpreted in terms of proton tunneling at low temperatures, a transition from tunneling to classical rotation of ammonia molecules between 40 and 54 K, and an ammonia diffusional transition with an activation energy of about 3 kcal/mole in the range 97-140 K.
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U2 - 10.1016/0009-2614(78)80073-6
DO - 10.1016/0009-2614(78)80073-6
M3 - Article
AN - SCOPUS:49349120042
SN - 0009-2614
VL - 53
SP - 578
EP - 582
JO - Chemical Physics Letters
JF - Chemical Physics Letters
IS - 3
ER -