【作者】 李莹； 吴迪； 李志儒；

【Author】 Li Ying,Wu Di Li Zhi-Ru Institute of Theoretical Chemistry,State Key Laboratory of Theoretical and Computational Chemistry,Jilin University,Changchun 130023,

【机构】 吉林大学理论化学研究所理论化学计算国家重点实验室；

【摘要】 非线性光学在全光学信息处理、光计算机、光通讯等许多方面起着重要的作用。非线性光学材料及其特性的研究是这一领域发展的重要基础。在之前的工作中,我们发现松束缚的电子对体系的非线性光学性质,尤其的第一超极化率（β₀）有重要影响。含松束缚电子的体系通常具有非常大的β₀值。而在碱金属化物[2]中,碱金属阴离子上的额外电子在空间中也是松束缚的,从而带给碱金属化物大的非线性光学响应。更多还原

【Abstract】 Since the past two decades,a great deal of work has been carried out to study the nonlinear optical properties（NLO） for many different types of NLO materials.In our previous works,we found that the systems with"alkalides"characteristics assessed the large NLO response because of the loosely-bound excess electrons. In this work,we design a new type of alkalide compounds,M⁺（N₃H₃）M’^-（M=Li,Na,and K）.In M⁺（N₃H₃）M’^-,the lone pairs of three N atoms push out the s electron of the M atom to form the M⁺ cation,and the electron is located in the diffuse s orbital of M’.Its electron cloud enwraps the whole M’ atom and thus creates an M’^- anion.The NBO calculations（see Table 1） show that the charges are 0.736～0.974 au.and -0.074～-0.333 au.for M and M’ atoms, respectively.It is obvious that the alkali atom M’ cannot completely seize the electron from the M atom because of the small electron affinity（0.60,0.54,and 0.49 eV for the Li,Na,and K atoms, respectively）.As a result,this excess electron is diffuse and easily excited,so the transition energies of the crucial excited state for M⁺（N₃H₃）M’^- are quite small.And consequently,theβ₀ values of M⁺（N₃H₃）M’^- are extraordinarily large.Especially,theβ₀ value of K⁺（N₃H₃）K^- is 6.9×10⁵ au.,which is twice of that of the organic alkalide（K⁺@2⁶adz）K^- with a cage complexant.更多还原