Photoluminescence experiments have been performed on GaAg-GaAlAs. quantum well structures with well widths ranging from 40Å to 145Å. Both the intrinsic and extrinsic transitions have been observed. Relatively strong interface-related luminescence is believed to be due to the presence of more trapped impurities at the interfaces.

To explain the differences in properties between the chalcogenide glassy semiconductors and the tetrahedrally-bonded semiconductors, a microscopic structural model is given in this letter. Based on this model, we can not only get two-level systems, negative-U pairs, and the Urbach rule, but also account for some recent experiments.

Semi-relativistic self-consistent electronic structure of AuGa₂ has been studied by means of linear muffin-tin orbitals method. The speculation of Switendick and Narath for the unusual Ga Knight shift in AuGa₂, and the s-d compensation mechanism occurring in the gold alloys given by Watson have been confirmed.

A comparatively detailed nonrelativistic investigation of the (p, π⁺) reaction has been made using Single-Nucleon-Mechanism. The results show that if eikonal distortion is a good approximation to high and medium energy scattering, SNM is inadequate to describe the reaction in producing asymmetry.

Infinite perturbed Rydberg states for molecules can be correlated with quantum defect parameters. We present our theoretical results of Rydberg series (ionization channels) for the NO molecules. In the f_σ channel, there exists a resonance which leads to the fine structure near the X-ray absorption K edges. The resonance energy decreases as the internuclear distance increases. Such relation can be utilized to diagnose the relevant bond-length of the molecules chemisorbed on the surface.

The magnetic of Nd_x Ni_1-x, amorphous thin films were studied. It was found that the effective magnetic moment of Ni atom (μ_Ni) approached to zero at X 0.26, and when X < 0.26 the composition dependence of μμ_Ni followed approximately μ_Ni = (0. 6-3X^1.2) μ_B It is found that the aspermagnetic and speromagnetic structures coexist in the amorphous Nd-Ni films with X < 0.26, and only speromagnetic structure exists for X < 0.26.

The ground state properties of the ferromagnetic (FM) Kondo lattice system are discussed by using the self-consistent field approximation. A phase diagram of the system including saturated ferromagnetic and FM-Kondo coexistent phases has been given. The results obtained can be used to explain the experimental observations for the first FM. Kondo lattice material Ce-Si_ξ.

The microwave transition between two ground hyperfine sublevels of Cs atom has been observed by opticl pumping and optical detecting. The maximum population difference between "0-0" sublevels in single laser pumping case is achieved. The "Ramsey pattern" of "0-0" clock Level transition and "Rabi" transition structures are obtained, and their main characters agree with the theoretical results. A better Cs beam atomic clock performance would be expected when the inject microwave frequency is locked into the center of the "0-0" cLock Level transition" In this experimental setup.

Starting from SSH model of trans-(CH)_x with finite length, all the localized vibrational modes of soliton have been figured out and the total number is found to be five. The first three coincide with those obtained in TLM model. Another two are new findings, the fourth is odd mode with three nodes and the fifth is a staggered mode with even parity.

Based on the Levinson theorem and using the method of Green's function, we derive the general expressions of fractional charge and fractional fermion number induced by the background field of t'Hooft-Polyakov magnetic monopole.

Positron lifetime measurements are applied to two amorphous alloys. In amorphous phase, annihilations from two kinds of positron traps are suggested. The positron lifetime is sensitive to structural relaxation and indicates pre-crystallization, and significantly decreases during crys-tallization. The observed positron responses to structural changes are well understood with quasi-crystalline model.