NH_4Cl和NH_4Br晶体中自陷态激子的辐射光谱和V_k心的吸收光谱研究

Study for Luminescence Energies of Self-Trapped Exciton (STE) and Absorption Energies of V_k-Center in NH_4Cl and NH_4Br Crystals

在单电子Hartree Fock近似的基础上采用扩展离子方法研究了NH4Cl和NH4Br晶体中自陷态激子(STE)的辐射光谱和Vk心的吸收光谱,根据变分法原理确定STE系统的最小能量及其相应的离子位移场,用赝势方法确定缺陷电子的态和能量,电子波函数和晶格弛豫由自洽迭代确定,研究结果表明自陷态激子的辐射光谱和Vk心的吸收光谱与实验符合得很好.

On the basis of one-electron Hartree-Fock approximation,the extended-ion method has been used to investigate luminescence energies of the Self-Trapped Exciton(STE) and absorption energies of the V_k-center in NH_4Cl and NH_4Br crystals. The energy and the corresponding equilibrium configuration of the crystal is determined by minimizing the total energy of the system. A hybrid pseudopotential method is used to determine the energy and states of the defect electron.The electron wavefunction and lattice relaxation are determined in a self-consistent way. The results show that the luminescence energies of the STE and the absorption energies of the V_k-center are in good agreement with the experimental results.