摘要:

We calculate the time evolution of excition density in a model dendrimer. Possible models with dendrimers for exciton condensates are proposed.

ISSN:1058-725X    

DOI:10.1080/10587250008038277

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In this work, we consider a cluster, which consists of small clusters with an anisotropy energy and suppose that the Hamiltonian of each cluster in the cluster is represented by the nonlinear sigma model. We apply a single spin model to the model clusters and calculate the time evolution of spin wavepacket. We demonstrate a magnetic field induced tunneling and elucidate its mechanism.

ISSN:1058-725X    

DOI:10.1080/10587250008038278

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The gas-adsorption behavior in microporous transition-metal complexes was investigated by the use of Monte Carlo simulations. We prepared the models of Cu3TMA2and Zn(BDC), which were crystallographically determined. The pressure dependence of the amount of adsorbed gases (argon, nitrogen, and hydrogen) was simulated at the boiling temperature of the gases. In the gas adsorption in Cu3TMA2, the effect of the charge distribution on the framework is negligible. However, the coordinating water narrows the cavity and stabilizes the adsorbed argon molecules. The amounts of adsorbed gases and the isosteric heats were calculated for Cu3TMA2and Zn(BDC) and the pictures of probability distribution of gases in the cavity were obtained. The probability distributions indicated that the adsorbed gases tend to be distributed as a zig-zag column in the capillary of Zn(BDC) and as a shape like a four-leaf clover avoiding the four benzene rings in the narrow cavity of Cu3TMA2.

ISSN:1058-725X    

DOI:10.1080/10587250008038279

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Magnetic interaction of Mn-π conjugated system, especially Mn(II)2-py-rimidine was investigated by theab initioUHF, post-UHF, and DFT approximations. The calculated effective exchange integrals (Jab) are negative, even though the m-phenylene type bridge is employed. This indicates that the superexchange effect plays a predominant role to determine the sign ofJabin Mn-π conjugated systems.

ISSN:1058-725X    

DOI:10.1080/10587250008038280

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The energies and transition moments of exciton states for dendritic molecular aggregates are calculated using a model Hamiltonian involving dipole-dipole interaction. Exciton pathways are found to be remarkably influenced by the constituent monomer units.

ISSN:1058-725X    

DOI:10.1080/10587250008038281

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The spatial contributions of exciton generation to polarizabilities (α) are elucidated for two types of molecular aggregate models with a dendritic structure, one of which involves a different type of dipole units such as transition metal compounds.

ISSN:1058-725X    

DOI:10.1080/10587250008038282

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The electronic structure of typicals= 1 Haldane gap compounds such as [Ni(NH2(CH2)3NH2)2N3]ClO4(NINAZ), [Ni(NH2CH2C(CH3)2CH2NH2)2N3]ClO4(NDMAZ) and [Ni(NH2CH2C(CH3)2CH2NH2)2N3]PF6(NDMAP) have been investigated by means of discrete variational (DV)-Xα molecular orbital calculation. The DV-Xα calculations of these compounds reveal the importance of the overlap population analysis of bridging N3−ligands, suggesting the tendency of the well-balance intramolecular overlap dispersion in the bridged N3−molecule is correlated with the larger Haldane gapEg.

ISSN:1058-725X    

DOI:10.1080/10587250008038283

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:1058-725X    

DOI:10.1080/10587250008038236

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor