A new lithium salt electride with an excess electron pair is designed, for the first time, by means of doping two sodium atoms into the lithium salt of pyridazine. For this series of electride molecules, the structures with all real frequencies and the static first hyperpolarizability (β0) are obtained at the second-order Møller-Plesset theory (MP2). Pyridazine H4C4N2 becomes the lithium salt of pyridazine Li-H3C4N2 as one H atom is substituted by Li. The lithium salt effect on hyperpolarizability is observed as the β0 value is increased by about 170 times from 5 to 859 au. For the electride effect, an electride H4C4N 2⋯Na2 formed by doping two Na atoms into pyridazine, the β0 value is increased by about 3000 times from 5 to 1.5 × 104 au. Furthermore, combining these two effects, that is, lithium salt effect and electride effect, more significant increase in β0 is expected. A new lithium salt electride Li-H 3C4N2⋯N2 is thus designed by doping two Na atoms into Li-H3C4N2. It is found that the new lithium salt electride, Li-H3C4N 2⋯Na2, has a very large β0 value (1.412 × 106 au). The β0 value is 2.8 × 105 times larger than that of H4C4N 2, 1644 times larger than that of Li-H3C4N 2, and still 93 times larger than that of the electride H 4C4N2⋯Na2. This extraordinary β0 value is a new record and comes from its small transition energy and large difference in the dipole moments between the ground state and the excited state. The frequency-dependent β is also obtained, and it shows almost the same trends as H4C4N2 ≪ Li-H3C4N2 ≪ H4C4N 2⋯Na2 ≪ Li-H3C4N 2⋯Na2. This work proposes a new idea to design potential candidate molecules with high-performance NLO properties.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry