Theory of nuclear spin relaxation of dilute spin systems

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5819094

Drabold, D A

A study of the effects of spatial disorder on the dynamical properties of spin systems is presented. The author has made a detailed study of the magnetic resonance and relaxation behavior of spins randomly diluted in a nonmagnetic host. The author has developed a method which quantifies to what extend nuclear or electronic spin wavefunctions are localized as a consequence of dilution. This methodology has been applied to the dilute dipolar lattice, and has had important implications to mixtures of (magnetic) ortho and (nonmagnetic) para molecular hydrogen. The author has calculated nuclear spin-lattice relaxation times for solid mixtures of ortho H{sub 2} and para H{sub 2} using standard moment techniques for high concentrations, and a stochastic theory of nuclear relaxation for low orthto concentrations. This work led to an understanding of many unresolved issues of hydrogen physics including a clear and accurate description of the temperature dependence of the nuclear relaxation times. Related methods have been applied to HD, where he has included spin diffusion between the H nuclei. The model he developed for relaxation for this system proved to be interesting in its own right because of its possessing exact solutions in physically interesting limits, and for the development of a method for solving the model by numerical simulation. For the H{sub 2} calculations he obtained good agreement with experiment, particularly for ortho H{sub 2} diluted in HD.

• Research Organization: Washington Univ., St. Louis, MO (USA)
• OSTI ID: 5819094
• Country of Publication: United States
• Language: English

Related Subjects

656002* -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANGULAR MOMENTUM
DISPERSIONS
ELEMENTS
FUNCTIONS
HYDROGEN
MAGNETIC RESONANCE
MATHEMATICAL MODELS
MIXTURES
NONMETALS
NUCLEAR MAGNETIC RESONANCE
PARTICLE PROPERTIES
RELAXATION
RELAXATION TIME
RESONANCE
SOLIDS
SPIN
SPIN-LATTICE RELAXATION
STOCHASTIC PROCESSES
TEMPERATURE DEPENDENCE
WAVE FUNCTIONS