外电场下二氧化锆的分子结构及其特性

对O原子采用6-311++G*基组,Zr原子采用aug-cc-pVTZ-PP基组,利用密度泛函(B3P86)方法优化得到了ZrO2分子的稳定构型,并研究了不同外电场(0—0.025 a.u.)作用下ZrO2基态分子键长、能量、电荷分布、偶极矩和能级的变化规律.在优化构型的基础上,利用含时密度泛函(TD-B3P86)方法研究了ZrO2分子在外电场作用下前6个激发态的激发能、跃迁波长和振子强度的激发特性.研究结果表明:随着电场强度的增大,Zr—2O的键长增大,而Zr—3O的键长均匀减少,总能量降低,偶极矩增大;最高占据轨道能量基本保持不变,最低未占据轨道和能隙均减小.电场的增大使得激发能减小,各个激发态跃迁波长均发生不同程度的红移现象,因而,利用外电场可以控制ZrO2的发光光谱范围在可见-红外区域扩展.

Molecular structure and properties of zirconiumdioxide under the external electric field

In order to study the influence of external electric field on ZrO₂, molecular structure of ZrO₂ ground state is optimized by density functional theory (B3P86) method with 6-311++G^* basis sets for O atom and aug-cc-pVTZ-PP for Zr atom. The effects of electric field ranging from 0 to 0.025 a.u. are investigated on bond length, total energy, charge distribution, dipole moment, HOMO (the highest occupied molecular orbital) energy level, LUMO (the lowest unoccupied molecular orbital) energy level and energy gap. The excitation energies, transition wavelengths and oscillator strengths under the same intense external electric fields are calculated by the time dependent density functional theory (TD-B3P86) method. The result shows that the bond length of Zr-2O and total energy increase with external field increasing, but the bond lengths of Zr-3O, LUMOs and energy gaps decrease, and HOMOs almost keep the same. The excitation energies decrease and the transition wavelengths of the six excited states are red shifted toward longer wavelength as the applied electric field increases. Therefore the spectral region of zirconiumdioxide molecule can be expanded in visible-infrared region by the use of external electric fields.