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Marshall, A. G.

Publications and source records attributed to Marshall, A. G..

3 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Effect of molecular shape and flexibility on gamma-ray directional correlations.

Huntress' formalism (1968) is used to calculate the angular correlation behavior for an ensemble of radioactive nuclei, each of which is bound to an asymmetric-top molecule. The calculation is carried out both in an extreme narrowing limit (rapid motion) and in an adiabatic limit (slow motion). The two limiting cases span nearly the whole range of rates of rotational reorientation. It is shown that the problem of internal rotation is formally identical to that of rotation of a symmetric-top molecule. The experimentally observable time-integrated anisotropy is plotted for several rates of internal rotational diffusion.

Marshall, A. G.↗
NASA NTRS1972

Effect of slow rotational diffusion on angular correlations.

The theory for perturbed angular correlations of gamma radiation has been extended to include the possibility of adiabatic variation in the interaction Hamiltonian, K, for the intermediate state. The calculation begins from a polycrystalline model. It is shown that adiabatic variation in K introduces a time dependence into the angles which express the orientation of the molecular frame. The relevance of the adiabatic limit to the use of perturbed angular correlations of gamma radiation for study of the motion of radioactive species in viscous media is discussed.

Marshall, A. G.↗