Rotation in Solid Mixtures of Neohexane and Cyclopentane from 20°K to Their Melting Points

Studies of the broadening of the proton spin resonance line have been made for solid solutions of neohexane and cyclopentane. A convenient apparatus for control of temperatures from 10°K to room temperature for such studies is described. The ``complex'' of one mole of neohexane with two moles of cyclopentane rotates in the solid state down to 65°K. In solid solutions with cyclopentane in excess of the complex, the complex rotates independently of the cyclopentane down to 66°K. The complex has no effect on the lower rotational transition of the cyclopentane which apparently nucleates.