1 research outputs found
Scattering of He-3 Atoms from He-4 Surfaces
We develop a first principles, microscopic theory of impurity atom scattering
from inhomogeneous quantum liquids such as adsorbed films, slabs, or clusters
of He-4. The theory is built upon a quantitative, microscopic description of
the ground state of both the host liquid as well as the impurity atom. Dynamic
effects are treated by allowing all ground-state correlation functions to be
time-dependent.
Our description includes both the elastic and inelastic coupling of impurity
motion to the excitations of the host liquid. As a specific example, we study
the scattering of He-3 atoms from adsorbed He-4 films. We examine the
dependence of ``quantum reflection'' on the substrate, and the consequences of
impurity bound states, resonances, and background excitations for scattering
properties.
A thorough analysis of the theoretical approach and the physical
circumstances point towards the essential role played by inelastic processes
which determine almost exclusively the reflection probabilities. The coupling
to impurity resonances within the film leads to a visible dependence of the
reflection coefficient on the direction of the impinging particle.Comment: 36 pages, 16 figure