Study of mechanism of hydrogen diffusion in separation devices. Progress report for 1980-1983

Technical Report · Mon Aug 15 04:00:00 EDT 1983

OSTI ID:5721256

Lee, M H

For the purpose of studying the mechanisms of hydrogen diffusion in separation devices e.g. transition-metal membranes, we have developed a microscopic dynamic model appropriate for describing the nonequilibrium statistical mechanics of hydrogen-in-a-metal. Using this model we have carried out a detailed analysis to obtain the autocorrelation function of density fluctuations in the model. Our model is built on the physical idea that, at low temperatures, spin clusters are the basic units or aggregates of transport. Our work can explain the reversed isotope effect in diffusion. We have also obtained an expression for the relative diffusivity, verifiable by experiments with tritium in metals. Our notion of spin clusters is novel. There is some evidence of their existence. The interstitial spin clusters are comparable to atomic and nuclear spin clusters, the only other natural spin clusters. Our demonstration of a long-time tail in the autocorrelation function is also novel. Diffusion can be anomalous if long time tails exist, a current topic in nonlinear behavior of fluids and solids. Our progress has been made possible by our development in the mathematical method of solving the generalized Langevin equation. This method is applicable to any time-dependent quantum many-body model. The underlying basis of this method is our discovery of a new orthogonalization process in Hilbert space, first since Gram and Schmidt over 100 years ago. Our process is simpler if Hilbert space is realized as is for all physical problems. To demonstrate the power and utility of our method we considered a well established model of metals, thereby discovering the existence of a low-frequency electronic mobility. This kind of intrinsic conductivity should exist in ensembles of all light particles, hence also relevant to hydrogen and its isotopes in metals.

• Research Organization: Georgia Univ., Athens (USA). Dept. of Physics
• DOE Contract Number: AS09-77ER01023
• OSTI ID: 5721256
• Report Number(s): DOE/ER/01023-6; ON: DE83016388
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
070100* -- Physical Isotope Separation
654001 -- Radiation & Shielding Physics-- Radiation Physics
Shielding Calculations & Experiments
656000 -- Condensed Matter Physics
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANGULAR MOMENTUM
ATOM TRANSPORT
BANACH SPACE
CORRELATION FUNCTIONS
DIFFUSION
ELEMENTS
EQUATIONS
FUNCTIONS
GASEOUS DIFFUSION PROCESS
HILBERT SPACE
HYDROGEN
HYDROGEN ISOTOPES
ISOTOPE SEPARATION
ISOTOPES
LANGEVIN EQUATION
MANY-BODY PROBLEM
MASS
MATHEMATICAL MODELS
MATHEMATICAL SPACE
MECHANICS
MEMBRANES
METALS
NEUTRAL-PARTICLE TRANSPORT
NONMETALS
PARTICLE PROPERTIES
RADIATION TRANSPORT
SEPARATION PROCESSES
SPACE
SPIN
STATISTICAL MECHANICS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS
VAN DER WAALS FORCES