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江元生, Jing Ma, Shuhua Li, * and Yuansheng Jiang*
J. Phys. Chem. A 1997, 101, 4770-4775,-0001,():
-1年11月30日
The low-lying excited states of benzenoid hydrocarbons with up to 22
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【期刊论文】Is Ferromagnetic Spin Coupling Constant within Homologous Di-and Triradicals?
江元生, Shuhua Li, Jing Ma, and Yuansheng Jiang*
J. Phys. Chem. 1996, 100, 4775-4780,-0001,():
-1年11月30日
By means of the powerful Lanczos algorithm, the nonempirical valence bond (VB) model has been applied to investigate the low-lying electronic states for three typical types of homologous
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【期刊论文】Polarizability and hyperpolarizability of push
江元生, Yinghong Sheng and Yuansheng Jiang*
J. Chem. Soc., Faraday T rans., 1998, 94 (13), 1829-1833,-0001,():
-1年11月30日
AM1 calculations are performed to study the non-linear optical (NLO) properties of push-pull quinones. The variations of molecular structure, linear (a) and NLO polarizabilities (b, c) for a set of push-pull quinones are discussed in terms of quinoid-benzenoid character (QBC), and the strength of donor-acceptor pairs The parameter already used for the polyene (dDA). dDA, bridge, is still valid in rationalizing the donor»acceptor strength for quinoid derivatives. In addition, we examined how an external electric-eld created by ìSparklesœ in the MOPAC package drives a quinoid molecule from the quinoid limit to the benzenoid limit, and how it aÜects the NLO properties. The results show that the eÜect produced by Sparkles is qualitatively similar to that of donor»acceptor pairs.
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江元生, SHUHUA LI, JING MA, YUANSHENG JIANG
J Comput Chem 23: 237-244, 2002,-0001,():
-1年11月30日
A linear scaling local correlation approach is proposed for approximately solving the coupled cluster doubles (CCD) equations of large systems in a basis of orthogonal localized molecular orbitals (LMOs). By restricting double excitations from spatially close occupied LMOs into their associated virtual LMOs, the number of significant excitation amplitudes scales only linearly with molecular size in large molecules. Significant amplitudes are obtained to a very good approximation by solving the CCD equations of various subsystems, each of which is made up of a cluster associated with the orbital indices of a subset of significant amplitudes and the local environmental domain of the cluster. The combined effect of these two approximations leads to a linear scaling algorithm for large systems. By using typical thresholds, which are designed to target an energy accuracy, our numerical calculations for a wide range of molecules using the 6-31G or 6-31G* basis set demonstrate that the present local correlation approach recovers more than 98.5% of the conventional CCD correlation energy.
coupled cluster, local correlation, linear scaling, localized molecular orbital
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【期刊论文】Effective Valence Bond Model Study on Conjugated Hydrocarbons Containing Four-Membered Rings
江元生, Jing Ma, Shuhua Li, and Yuansheng Jiang*
J. Phys. Chem., Vol. 100, No.37, 1996 15069,-0001,():
-1年11月30日
By employing the Lanczos method, the effective valence bond model (EVB) is exactly solved for a series of conjugated hydrocarbons with four-membered rings. Several indices calculated from the EVB ground-state energies and wave functions are applied to interrelate with bond lengths, stabilities, and reactivities of these systems. Our results agree well with related experimental observations and deductions of molecular orbital theory. The failure of the classical valence bond theory in these systems is also exposed.
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