Role of Excess Electrons in Nonlinear Optical Response

Abstract

The excess electron is a kind of special anion with dispersivity, loosely bounding and with other fascinating features, which plays a pivotal role (promote to about 10(6) times in (H2O)3{e}) in the large first hyperpolarizabilities (β0) of dipole-bound electron clusters. This discovery opens a new perspective on the design of novel nonlinear optical (NLO) molecular materials for electro-optic device application. Significantly, doping alkali metal atoms in suitable complexants was proposed as an effective approach to obtain electride and alkalide molecules with excess electron and large NLO responses. The first hyperpolarizability is related to the characteristics of complexants and the excess electron binding states. Subsequently, a series of new strategies for enhancing NLO response and electronic stability of electride and alkalide molecules are exhibited by using various complexants. These strategies include not only the behaviors of pushed and pulled electron, size, shape, and number of coordination sites of complexants but also the number and spin state of excess electrons in these unusual NLO molecules.

Chemical structure and mechanical properties of soda lime silica glass surfaces treated by thermal poling in inert and reactive ambient gases

“…Thermal poling was originally studied as a process to induce nonlinear optical properties and electro‐optic effects in isotropic glass materials; it was recently reported that thermal poling can also be used as an efficient way to increase the indentation fracture toughness of SLS glass . Thermal poling is typically done by applying a high electric field (on the order of MV/m) across the glass at an elevated temperature, which facilitates diffusion of Na + ions from the surface in contact with the anode to the surface in contact with the cathode, and then cooling the sample while holding the electric field to freeze any nonequilibrium distribution or polarization of ions in the glass matrix .…”

Recent Progress on the Design, Characterization, and Application of Superalkalis

“…[8,55] First, as eries of supersalts (BLi 6 ) + (X) À (X = F, LiF 2 ,B eF 3 ,B F 4 ), [8a] (M) + (BF 4 ) À (M = FLi 2 ,O Li 3 ,N Li 4 ), [8b] (M 3 O) + (Al 13 ) À (M = Na, K), [8c] (Na 2 X) + (Y) À (X = SCN, OCN, CN;Y= MgCl 3 ,Cl, NO 2 ) [30a] were theoretically constructed and predicted to be new inorganic NLO molecules in view of their considerable NLO responses. Moreover,w ith their superiora bility to offer valence electrons, superalkalis can serve as excellent sourceso fe xcess electrons [57] to design unique compounds,s uch as electrides [58] and alkalides, [59] whiche xhibit extraordinarily large NLO responses. Wang et al [8d] presented the first evidencef or superalkalibased electrides (M 3 O) + (e@C 20 F 20 ) À (M = Na, K), where the excess electron is protected in the C 20 F 20 cage with as ufficient interior electron attractive potential (see Figure9a).…”

A quantum chemical study on the remarkable nonlinear optical and electronic characteristics of boron nitride nanoclusters by complexation via lithium atom

“…It is noteworthy that selecting a proper method to calculate the hyperpolarizability of a system is a challenging task. The quadratic configuration interaction including single and double substitutions (QCISD) and the second-order Møller-Plesset perturbation (MP2) methods are suitable to for calculating hyperpolarizability, but they are very costly for relatively larger systems [17,42]. On the other hand, the B3LYP method has overestimated the hyperpolarizabilities for some large systems [43].…”