Theoretical Study On Structures And Nonlinear Optical Properties Of Superatoms Inducing Phenalenyl System

Due to the applications in optical communication, laser technology and optical switching, the study of designing and synthesizing the non-linear optical ?NLO? properties has become a hot subject. In this work, we employed density functional theory ?DFT? to design a series of new molecules containing Phenalenyl, and investigated their structures and NLO properties.The main contributions are as follows:1. In this work, two interesting complexes ?Li₃O-PLY and Li₃-PLY? were constructed by Phenalenyl radical and superalkali atoms. Why are they interesting? Firstly, for Li₃O-PLY and Li₃-PLY. although the charge transfer between superalkali atoms and PLY is similar, the sandwich-like charge distribution for Li₃O-PLY causes a smaller dipole moment than that of Li₃-PLY. Secondly, their UV-vis absorption show that the maximum wavelengths for Li₃O-PLY and Li₃-PLY display a bathochromic shift compared to PLY. Moreover, Li₃-PLY has two new peaks at 482 and 633 nm. Significantly. Frontier molecular orbital ?FMO? analysis has shown that Li₃-PLY has a larger diffuse electron cloud in highest-occupied molecular orbitals ?HOMO?, which leads to larger ?0 values. The ?0 values of Li₃-PLY ?4943-5691 a.u.? are much larger than that of Li₃O-PLY ?225-347 a.u.?. Further, the ?HRS values of Li₃O-PLY decrease slightly while ?HRS of Li₃-PLY increase dramatically with increasing frequency.2. In this work, we designed two molecules, Li₃O…C₁₃H₉ ?1a? and BeF₃…C₁₃H₉ ?1b?. Interestingly, owing to the inductive effect of superatoms, an electron is transferred from Li₃O to Phenalenyl in la, while an electron is transferred from Phenalenyl to BeF₃ in 1b. Further, we employed la and 1b as building blocks to assemble two novel molecules with 2e/12c bonds:Li₃O…(C₁₃H₉)2…BeF₃ ?2a? and Li₃O…(C₁₃H₉)2…BeF₃ ?2b?. Remarkably.2a and 2b with novel 2e/12c bonds exhibit a dramatic interlayer charge-transfer character, which results in a significant difference of dipole moments ???: 2.6804 for 2a and 3.8019 Debye for 2b? between the ground state and the crucial excited state. As a result, the static first hyperpolarizabilities ??0:5154 for 2a and 12500 a.u. for 2b? are considerably larger than the values of 347 a.u. for la and 328 a.u. for 1b.It is our expectation that the results of the present work might provide benficial information for further theoretical and experimental studies.