Application of a screened INDO model (INDO/S) to spectroscopic properties of TCNQ and its anions

Theoretical Chemistry Accounts - An INDO model Hamiltonian, incorporating screening within the π-system and parametrized particularly to describe dynamical properties (photoemission and...     

Structure and solvation of nitrobenzene and 1,4-dinitrobenzene radical anions

An INDO method extended to include a contribution from the solvent by means of an effective solvent field (INDO-ESF) and based on properly optimized geometries is applied to the nitrobenzene and 1,4-dinitrobenzene radical anions. The hyperfine couplings and their solvent sensitivities are reproduced within a planar structure of the radicals. The behaviour of¹⁴N and¹⁷O splittings in derivatives with twisted nitro groups is accounted for with no difficulty.     

Theoretical Investigation on Electronic Transition of Tris(8-quinolinolate) Aluminum Grafted on Poly(p-phenylenevinylene) Units with the Localized-density-matrix Method

An unsystematic molecule PPV‐Alq₃ [3‐(4‐((E)‐2‐(8‐hydroxy‐3‐(4‐styrylstyryl)quinolin‐Alq₂‐6‐yl)vinyl)‐ styryl)‐6‐(4‐styrylstyryl)quinolin‐8‐olate‐Alq₂; q=8‐quinolinolate], which combines poly(p‐phenylenevinylene) with tris(8‐quinolinolate)aluminum, has been studied using a localized‐density‐matrix method. The absorption spectra and electronic transition properties were analyzed and compared with both intermediate neglect of the differential overlap method and the localized‐density‐matrix method. Great efforts have been made on investigating conjugated system on the absorption properties as these can be particularly important for many applications. Two different absorptions of the special molecule, tris(8‐quinolinolate)aluminum grafted on poly(p‐phenylenevinylene) units, were further discussed with density matrices. For the molecule, the first absorption peak is at 413 nm near the purple light. Two 8‐hydroxyquinolines have very slight electronic transition properties. Another absorption peak is at 237 nm. The second characteristic peak of molecule is completely different from that of the first one, which comes from contribution of 8‐hyroxyquinolines in the two different side chains. Our studies show that electronic transition properties of poly(p‐phenylenevinylene) can be effectively tuned by grafting tris(8‐quinolinolate)‐aluminum on poly(p‐phenylenevinylene) from the standpoint of transition energies, frontier molecular orbitals and density matrices.     

C70O2可能异构体的结构和电子光谱的理论研究

用AM1、PM3及INDO系列方法研究了C₇₀O₂可能异构体的结构和稳定性.在C₇₀O稳定构型的基础上,考察了C₇₀O₂的45种异构体.结果表明,两个O原子加在碳球极端处同一个六元环内不等价的6/6键上形成环氧结构的构型最稳定.在优化构型的基础上,进行电子光谱计算,并与C₇₀和C₇₀O进行了比较.     

C60异噁唑环衍生物的结构、电子光谱和非线性光学性质的研究

The AM1 semiempirical calculation method was employed to study the structures and electronic properties of a series of isoxazolo fullerene derivatives. Based on the AM1 geometry optimization, the electronic spectra of molecules were studied by using ZINDO/CIS methods. The results indicated the HOMO LUMO energy gaps of those isoxazolo fullerenes were lower than that of C60. There existed the intramolecular electron transfer from the additional section to C60 moiety. The electronic spectrum data showed that the exception of the absorption was beyond 400 nm.The results were in good accordance with the experiment results. Nonlinear optical susceptibilities α, β and γ of molecules were calculated according to Finite Field(FF)/AM1, and the influence of molecular structures on nonlinear optical properties was examined.     

C80n(D2,Ih)的Jahn-Teller畸变和电子光谱

Jahn-Teller distortion of C80n(D2,Ih) was studied by the INDO method. It shows that C80(D2) is more stable than C80(Ih), which is in agreement with the experiment. Jahn-Teller distortion did not take place in C80n(D2) but happened in some of ions for C80n(Ih). Total energy of C80n was affected by the increase in absolute values of electric charges. Electronic spectra of C80 were calculated for the first time. Not only spectrum data of C80 consistent with the experiment were obtained but also electronic spectra of C80n were predicted where the electronic transition was assigned theoretically. The reason for the red shift of UV bands for C80n(D2) compared with that of C80(D2) and the blue-shift of peaks for C80n(Ih) relative to C80(Ih) is that the LUMO-HOMO energy gap of C80n(D2) is less than that of C80(D2) whereas the energy gap of C80n(Ih) is bigger than that of C80(Ih).     

多面体碳烷的分子轨道方法研究

利用INDO自洽场方法和Edmiston-Ruedenberg定域化方法,计算了多面体碳烷C_2nH_2n(n=2,3,4,5和10)及其骨架C_2n,讨论了它们的电子结构、稳定性和化学键性质。     

C70NH的结构和光谱的理论研究

摘要本文用INDO系列方法对C70NH的8种异构体构型进行计算，结果表明最稳定的构型是N原子加在C3-C3键和C4-C4键上形成具有CS对称性且不开环的三元环结构。研究了这两种最稳定构型的电荷分布，指出了C70NH的8种构型的^13CNMR谱。进行了UV-Vis光谱计算，结果表明C70NH主峰与C70一致，并在500nm以上产生特征吸收峰；C70NH与C70。相比将发生UV谱带红移的现象，同时讨论了谱带红移的原因。