外电场下GaN的特性研究
Properties of ground state for GaN in different external electric fields

以6-311G(3df,3pd)为基组，采用B3PW91方法优化得到GaN基态分子的几何结构，并探究了电场对GaN分子基态能量、电荷布居数、键长、偶极矩、振动频率、红外光谱强度、HOMO、LUMO能级影响。研究表明：电场时，谐振频率值为576.2218 cm-1，与实验值484.9 cm-1很接近。有电场时，键长、偶极矩、能隙Eg、电荷布居数、红外谱强度、HOMO和LUMO能级随电场的增大而减小；谐振频率和分子总能量随电场的增加而增加。谐振频率和红外谱强度对电场有着明显的依赖关系，这对材料的光学特性研究有提供理论参考。
Density functional theoretical (B3PW91) method with 6-311G(3df,3pd) basis sets had been performed on the total energy, equilibrium structure, dipole moment, atomic charge distribution, infrared intensities, harmonic frequencies, the highest occupied molecular orbital(HOMO) energy level, the lowest unoccupied molecular orbital(LUMO) energy level, an energy gaps of the GaN ground state molecules in different intense electric fields. The results show that the harmonic frequency (f=576.2218 cm-1) is close to experiment with data (f=484.9 cm-1). With the increase of the external field, the bond length, electric dipole moment, atomic charge distribution, energy gap, infrared intensities, HOMO and LUMO energy are proved to decrease. But harmonic frequencies and total energy are proved to increase. The external electric field has a significant effect on the harmonic frequencies and infrared intensities. These will provide important theoretical reference for the studies of optic properties with materials.