Large Clusters and Extrapolated Oligomers

Mosley et al. have applied different density functional methods for a molecular hydrogen chain.134 The results obtained with the aid of Romberg s extrapolation procedure135 overestimate the static longitudinal polarizability as compared to the CHF results. 

In two recent papers144,145 a symmetrized Density Matrix Renormalization145 

Group method was applied for dynamic aL and yL using ID Hubbard and U-V models and a Hubbard-Peierls model Hamiltonian in the case of linear polyenes. 

Wortmann and Bishop14 have successfully extended Onsager s148 reaction field model to non-linear optical properties in condensed media,147 which is applicable in any order of dynamic hyperpolarizabilities. 

It should be emphasized that it is impossible to mention all the large number of papers which have appeared in this field in the last few years. Therefore, we have tried to select the most interesting looking ones which have either introduced new theoretical techniques or attacked new physical problems. 

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