Measurements of diffuse and specular scattering of sup 4 He atoms from sup 4 He films

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:6955545

Mukherjee, S

We have observed scattering of {sup 4}He atomic beams from films of {sup 4}He on glass and mica substrates. The specular reflection coefficient, or reflectivity, R(k,{theta}) was measured as a function of the angle of incidence {theta} and the wavevector k of the incident atoms, and the thickness of the film. The film thickness d varied from 45 {angstrom} to macroscopic values. In contrast to previous experiments on scattering from 10 cm deep liquid, we observed not only the expected specular reflection, but also isotropic diffuse scattering. To explain the diffuse signal, we assume that most of the incident atoms are converted into phonons, rotons and ripplons at the surface of the film. The phonons and rotons are scattered at the substrate, and subsequently evaporate an isotropic distribution of atoms.

• Research Organization: Ohio State Univ., Columbus, OH (USA)
• OSTI ID: 6955545
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HELIUM 4
SCATTERING
REFLECTIVITY
CALCULATION METHODS
DATA ANALYSIS
EXPERIMENTAL DATA
FILMS
GLASS
MEASURING INSTRUMENTS
MEASURING METHODS
MICA
PHONONS
ROTONS
DATA
EVEN-EVEN NUCLEI
HELIUM ISOTOPES
INFORMATION
ISOTOPES
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
QUASI PARTICLES
STABLE ISOTOPES
SURFACE PROPERTIES
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory
656003 - Condensed Matter Physics- Interactions between Beams & Condensed Matter- (1987-)