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).     

C78O异构体的电子结构和光谱

为了模拟C78单加成物的加成位置和稳定性,并预测其光谱性质,用INDO系列方法对基于C2v-C78之上的C78O所有可能的34个异构体结构和电子光谱进行理论研究．结果表明,C78O的最稳定异构体是O加在位于C2v-C78短轴上的73,78-键上且形成环氧结构的6／6异构体,O的原子轨道对73,78-C78O中的HOMO能量降低起重要作用．讨论了电子跃迁性质和73,78-C78O电子光谱的长波吸收峰与母体相比发生蓝移的原因．     

ELECTROREDUCTION MECHANISM OF Ni(DMG)-2 COMPLEX STUDIED WITH QUANTUM CHEMICAL METHOD

The electronic structures of the species Ni(DMG)_2, (Ni(DMG)_2)~- and (Ni(DMG)_2)_(2-) have been studied by INDO quantum chemical method. The results have clearly shown that in the first stage of the electroreduction of Ni(DMG)_2, one electron interacts with the d orbitals on the nickel atom, while in the further stage the second electron interacts with the p orbitals on the nitrogen atoms. It conforms with our electrochemical experimental studies which showed that not only Ni(Ⅱ) is reduced but also DMG is catalytically reduced during the reduction of Ni(DMG)_2.     

Quantum-Chemical Calculations of the Excited Electronic States of the Prodan Molecule and Its Complexes in Water

A quantum-chemical calculation of the prodan molecule and its complexes in water for the geometry of the ground and fluorescent states is carried out. To describe the fluorescent state, changes in the electronic state (population) on bonds and atoms during transition of the molecule into an excited state are taken into account. A model of interaction of the prodan molecule with a polar proton-donor solvent (water) is suggested. It is shown that interaction with the ionic forms (H₃O₊ provides an explanation for the sensitivity of prodan to the solvent (displacement of the fluorescence bands). The nature of the electronic excited states of the prodan molecule and its complexes has been investigated. The constants of the rates of radiative and nonradiative processes and the fluorescence quantum yields have been calculated. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 330–334, May–June, 2005.     

Theoretical studies on structures and UV-Vis spectra of C_(70)O

Systematic studies on eight isomers of C70O were performed by means of INDO methods It has been indicated that the O atom is mainly added to the C1-C2 or C3-C3 bond and an epoxide feature with C1 symmetry is formed.Based on the optimized geometries,the UV-Vis spectra were calculated.It has been found that the main peaks of C70O resemble those of C70 and the characteristic absorptions beyond 460 nm are produced,which is m agree ment with the experimental results.Theoretical assignments about the absorptions were carried out and the reason for the red-shift of the absorptions was discussed.C70O is probably composed of four isomers according to the calculated results.     

青蒿素分子的电子结构,紫外和圆二色谱的量子化学研究

以ＩＮＤＯ／Ｓ－ＣＩ法对青蒿素分子进行了量子化学研究。结合实验结果讨论了其紫外光谱和圆二色谱。     

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.     

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...     

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.     

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。