Fonseca Sàvio, Dos Santos Neidy S S, Georg Herbert C, Fonseca Tertius L, Provasi Patricio F, Coutinho Kaline, Canuto Sylvio, da Cunha Antônio R, Gester Rodrigo
Programa de Pós-Graduação em Química, Universidade Federal do Sul e Sudeste do Pará, Marabá, Pará 68507-590, Brazil.
Instituto de Física, Universidade Federal de Goiás, Goiânia, Goiás 74690-900, Brazil.
ACS Omega. 2024 Sep 20;9(39):40583-40591. doi: 10.1021/acsomega.4c04240. eCollection 2024 Oct 1.
The photophysics and nonlinear optical responses of a novel nitrothiazol-methoxyphenol molecule were investigated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods with the polarizable continuum model to take the solvent effect into account. Special attention is paid to the description of the lowest absorption band, characterized as a strong π → π* state in the visible region of the spectrum. The TD-DFT emission spectrum analysis reveals a significant Stokes shift of more than 120 nm for the π → π* state in gas phase condition. The results show a great influence of the solvent polarity on the nonlinear optical (NLO) response of the molecule. Specifically, the second harmonic generation hyperpolarizability β(-2ω; ω, ω) shows a large variation from gas to aqueous solvent (82 × 10 to 162 × 10 esu), exhibiting notably higher values than those reported for standard compounds such as urea (0.34 × 10 esu) and -nitroaniline (6.42 × 10 esu). Furthermore, a two-photon absorption analysis indicates a large cross-section (δ = 77 GM) with superior performance compared to several dyes. These results make the molecule quite interesting for nonlinear optics.
采用密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）方法，并结合极化连续介质模型以考虑溶剂效应，对一种新型硝基噻唑-甲氧基苯酚分子的光物理性质和非线性光学响应进行了研究。特别关注了最低吸收带的描述，其在光谱的可见光区域被表征为强π→π态。TD-DFT发射光谱分析表明，在气相条件下，π→π态的斯托克斯位移超过120nm。结果表明溶剂极性对分子的非线性光学（NLO）响应有很大影响。具体而言，二次谐波产生超极化率β(-2ω; ω, ω)在从气相到水相溶剂中显示出很大变化（从82×10到162×10 esu），其值明显高于尿素（0.34×10 esu）和对硝基苯胺（6.42×10 esu）等标准化合物的报道值。此外，双光子吸收分析表明该分子具有较大的截面（δ = 77 GM），与几种染料相比性能更优。这些结果使得该分子在非线性光学方面颇具吸引力。
