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.
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry