Theoretical Study on the Compounds of Chlorine Fluoride (ClF3, ClOF3) and Superhalogens (BeF2, MgF2): Preferred Structures and Significant Nonlinear Optical Properties

A new class of chlorine fluoride-superhalogen compounds, ClF3(O)–MF2, (M = Be, Mg) are theoretically studied using density functional theory (DFT). The results show that the interaction between ClF3(O) and MF2 is strong and exist in ionic form. Bond energies of these compounds are in the range of 143.23 to 161.40 kcal mol–1 at the level of B3LYP/6-311++G(d, p), which are larger than the traditional ionic bond energy of 130.1 kcal mol–1 for LiF. The energy gaps between the highest occupied and lowest unoccupied molecular orbitals are large thus they are stable at the normal temperature and pressure. Furthermore, because of their delocalized electron character, these species exhibit extraordinarily large first hyperpolarizabilities with α0 ranging from 45.26 to 55.15 a.u. The present investigation provides hints to scientists in extending the research in atomic dimension to direct the interaction between superatoms, and using superatoms as building blocks to synthesize novel meaningful materials with unusual performences such as nonlinear optical materials.