%0 Journal Article %T Electronic Absorption Spectra and Third-Order Nonlinear Optical Property of Dinaphtho[2,3-b:2¡¯,3¡¯-d]Thiophene-5,7,12,13- Tetraone (DNTTRA) and Its Phenyldiazenyl Derivatives: DFT Calculations %A Ziran Chen %A Yujin Zhang %A Zhanrong He %A Yonghua Guan %A Yuan Li %A Hongping Li %J Computational Chemistry %P 43-60 %@ 2332-5984 %D 2020 %I Scientific Research Publishing %R 10.4236/cc.2020.84005 %X Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2¡¯,3¡¯-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-¦Ð-A-¦Ð-D structures. The third-order NLO coefficients ¦Ã (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 107 atomic units (10-33 esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH3)2 or -NHCH3) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained. %K Azobenzene %K Dinaphtho[2 %K 3-b:2¡¯ %K 3¡¯-d]Thiophene-5 %K 7 %K 12 %K 13-Tetraone %K Density Functional Theory %K Electronic Absorption Spectra %K Third-Order Nonlinear Optical Property %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=103869