Light scattering studies of solids and atomic vapors

Technical Report · Fri Sep 01 04:00:00 EDT 1978

DOI:https://doi.org/10.2172/6603478· OSTI ID:6603478

Chiang, T C

The general technique of light scattering and luminescence was used to study the properties of a number of material systems. First, multi-phonon resonant Raman scattering up to four phonons in GaSe and one- and two-phonon resonant Raman scattering in the mixed GaS/sub x/Se/sub 1-x/ crystals with x < or = 0.23 were investigated. Second, the observation of one-phonon resonant Raman scattering in HfS/sub 2/ is reported. The result is used to determine the position of the direct gap of HfS/sub 2/. Third, the first observation of the ..pi..-polarized one-magnon luminescence sideband of the /sup 4/T/sub lg/ (/sup 4/G) ..-->.. /sup 6/A/sub lg/(/sup 6/S) excitonic transition in antiferromagnetic MnF/sub 2/ is presented. An effective temperature of the crystal is deduced from the simultaneously observed anti-Stokes sideband emission. Multi-magnon (< or = 7) excitonic luminescence sidebands were also observed in MnF/sub 2/, KMnF/sub 2/, and RbMnF/sub 3/ using pulsed excitation and detection. A simple model based on two-ion local exchange is proposed to explain the results qualitatively. Fourth, the first observation of two-magnon resonant Raman scattering in MnF/sub 2/ around the magnon sidebands is reported. A simple theoretical description explains the experimental observations. Fifth, a detailed theory of exciton-exciton interaction in MnF/sub 2/ is developed to explain and to predict the experimental results on two-exciton absorption, high level excitation, and exciton--exciton scattering. Sixth, Brillouin scattering was used to obtain the five independent elastic constants of the layered compound GaSe. The results show clear elastic anisotropy of the crystal. Resonant Brillouin scattering near the absorption edge was also studied, but no resonant enhancement was found. Seventh, two-photon parametric scattering in sodium vapor was studied. Phase matching angles and scattering cross sections are calculated for a given set of experimental conditions.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6603478
• Report Number(s): LBL-8222
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals &amp; Alloys-- Physical Properties
360603* -- Materials-- Properties
ALKALI METAL COMPOUNDS
ALKALI METALS
ANTIFERROMAGNETISM
BRILLOUIN EFFECT
CHALCOGENIDES
COHERENT SCATTERING
ELEMENTS
EXCITONS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GALLIUM COMPOUNDS
GALLIUM SELENIDES
GASES
HAFNIUM COMPOUNDS
HAFNIUM SULFIDES
HALIDES
HALOGEN COMPOUNDS
INELASTIC SCATTERING
LUMINESCENCE
MAGNETISM
MAGNONS
MANGANESE COMPOUNDS
MANGANESE FLUORIDES
MANGANESE HALIDES
METALS
POLARIZATION
POTASSIUM COMPOUNDS
POTASSIUM FLUORIDES
QUASI PARTICLES
RAMAN EFFECT
RESONANCE SCATTERING
RUBIDIUM COMPOUNDS
RUBIDIUM FLUORIDES
SCATTERING
SELENIDES
SELENIUM COMPOUNDS
SODIUM
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VAPORS