Higher Exciton States Research Articles

Multiple LO Phonon Scattering in Orthorhombic Thallous Iodide

The scattering spectrum of orthorhombic TlI has been measured at 2 K under the resonant excitation around the first exciton energy of 2.87 eV. The spectrum is composed of multiple LO phonon lines showing a characteristic intensity alternation as was found in indium halides. The dependence of intensities of the LO lines on the incident photon energy has been investigated. The LO lines show a resonant enhancement in intensity with 2 s and higher exciton states as well as with the 1 s exciton state. It is also found that some of the excitons relaxed to the band bottom are transformed into photons with the emission of 2LO phonons rather than 1LO phonon.

Angular distribution of neutrons from precompound decay in inelastic scattering

Precompound angular distribution in inelastic scattering of 14 MeV neutrons are analysed in terms of surface interaction with the higher exciton states taken into account. This model is applied to some (p, α) reactions also.

Study of Absorption Spectra of Excitons in Cu2O by Wavelength Modulation Technique

The wavelength derivative absorption spectra of Cu 2 O have been measured in the energy regions of the yellow and green exciton series over a wide temperature range. Three phonon assisted indirect transition edges are newly found at 4.2 K, and the structures associated with direct transitions to the 1s state and the higher exciton states are observable up to room temperature. By analysing the impurity associated transition and using the Rydberg constants for both the yellow and the green exciton series, we determine the effective mass of the electron in the conduction band and those of the holes in the valence bands to be m e * ≃0.99 m 0 , m l h * ≃0.64 m 0 (light hole) and m h h * ≃1.40 m 0 (heavy hole).