【摘要】 利用基于密度泛函理论的有限电场方法对Pb_nSn(n=1～19)团簇的电偶极矩和极化率进行研究.Pb_nSn(n=1～19)合金团簇的高对称性抑制其电偶极矩的产生.在团簇原子总数N<14时,团簇的电偶极矩与能隙表现出相反的变化趋势(同一尺寸下,高能隙与低电偶极矩相对应),然而在14≤N≤19范围内,由于构型生长方式的转变,能隙与电偶极矩展现出相同的演化趋势.研究所得的极化率与实验值在部分尺寸相符合较好,但总体上与实验值还有一定的差别,这可能是实验中包含混合态或激发态的缘故.更多还原

【Abstract】 The electric dipole moments and polarizabilities of Pb_nSn(n=l~19) clusters have been studied by finite field method based on density functional theory(DFT).The high-symmetry of cluster for-bidders the generation of electric dipole moment.Then,the electric dipole moments and energy gaps of clusters show opposite trend with N<14(the high-energy gaps correspond to low electric dipole moments). Yet,the electr c dipole moments and energy gaps evolution present same pattern with 14≤N≤19,which is due to the change of structures growth pattern.Importantly,the polarizabilities correspond to the experimental data well in some dimensions,but in general with the experimental data also certain differences,which may be caused by the mixed states or excite states included in the experiment.更多还原