Theoretical investigation of organic-inorganic hybrid crystal: Optical transparency and quadratic harmonic coefficients of 2-Amino-5-Nitropyridinium chloride
Affiliations: [a] State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Fujian, Fuzhou, 350002 China | [b] Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Fujian, Fuzhou, 350002 China
Abstract: The IR and UV absorption cut-offs (λIR and λUV) of an organic-inorganic hybrid nonlinear optical (NLO) crystal, 2-amino-5-nitropyridinium chloride (2A5NPCl), were investigated in the framework of density functional theory. The macroscopic quadratic NLO coefficients of the crystal were evaluated at the MP2/6-31+G** level coupled with the oriented-gas model. The calculated results reveal that the λIR and λUV are governed by the asymmetric N–H stretch of NH2 group and the charge transfer (CT) transition from Cl− to 2A5NP+, respectively. The optical transparency has been determined in the region 407–1415 nm. The analyses of the electronic absorption spectrum show that the CTs of both Cl− → 2A5NP+ and π→p∗ within 2A5NP+ moiety make dominant contributions to the β values. The studies of the oriented-gas model show that the crystal has large NLO coefficients.
Keywords: IR absorption cut-off, UV absorption cut-off, optical transparency, charge transfer, the oriented-gas model, macroscopic quadratic NLO coefficients
