Ab initio polarizability study of polypyrrole

Abstract

The static polarizability and first hyperpolarizability of the water trimer anion: Ab initio study Ab initio study of the dipole polarizability and the first hyperpolarizability of heterocyclics AIP Conf. Proc. 330, 74 (1995); 10.1063/1.47853 Ab initio studies of the polarizabilities of retinal analogsThe longitudinal polarizability, ␣ zz , and second order hyperpolarizability, ␥ zzzz , of the (C 4 H 3 N͒ R H 2 oligopyrroles, where Rϭ1Ϫ9, are determined at the Hartree-Fock ͑HF͒ level of theory using a 6-31G basis set. The effect of electron correlation is taken into account using Moller-Plesset perturbation theory through second order for the Rϭ1Ϫ5 oligopyrroles. Methods for extrapolation to the infinite polymer values are explored. The convergence behavior of the correlated results as a ratio with the corresponding HF values may indicate that a scaled HF procedure could be appropriate for finding correlated estimates to the infinite polymer property values. We also propose a generalized finite field recipe which can easily be used in conjunction with popular black-box electronic structure programs for determining molecular polarizabilities through second order. The ␣ zz and ␥ zzzz values obtained from using this procedure on a variety of polyacetylene and polypyrrole oligomers are in excellent agreement with those derived through analytical procedures.

Hartree–Fock static longitudinal (hyper)polarizability of polyyne

“…Thus, frequency dispersion and the effect of correlation can be determined from the static HF value and results for smaller oligomers. Preliminary findings for polypyrrole 24 are consistent with those of PA as far as electron correlation is concerned. The calculation of the static hyperpolarizability, then, is the first step in determining the NLO properties of a conjugated polymer such as polyyne.…”

“…To find ␣ L we employed the FF recipe suggested in Ref. 24. For ␥ L it was necessary to slightly modify the latter procedure for the larger oligomers by using fields smaller than those recommended.…”

“…As noted already, the same appears to be true for polypyrrole. 24 Whether the asymptotic behavior described in the preceding paragraph is general or not remains to be established. A good test case is the conjugated polymer polyyne.…”

Structural, energetic and response electric properties of cyclic selenium clusters: an ab initio and density functional theory study

“…In order to obtain an approximate estimate of BE/n in the limit for n ? ?, we adopted the following extrapolation fitting expression [83,84]:…”

A Quantum‐Mechanical QSAR Model to Predict the Refractive Index of Polymer Matrices

“…We carried out this calibration in this study because HOMO-LUMO gaps are often associated with RI, and energy gaps between molecular orbitals become smaller as polymer chains lengthen. If the results of our QSAR predictions change had significantly when using longer chains as polymer structural representatives, then longer chain lengths would have been required to adequately model the polymer [20]. Since the results for the various models are very similar, the dimer model was chosen as one that had some polymer structure present, but was not too computationally demanding.…”