Model calculations of polarizabilities of polyene chains: Oligomers and infinite polymers

Abstract

In order to find the best methods for calculating the (hyper)polarizabilities of long oligomers and infinite polymers, we first propose in this paper to calculate the linear static electric polarizabilities of regular and alternant polyene chains by using the Huckel approach. For these calculations, the perturbation approach is used to obtain second-order response properties. We have derived this formulation by starting from the polarization propagator within an approximation which consists of projecting the superoperator resolvent form on a basis set of operators composed of only single excitations. For polyenes of different degrees of bond alternation, we obtained in the same Huckel approximation the asymptotic value of the polarizability per unit cell by using the Bloch functions in the Genkin and Mednis technique of calculating polymeric polarizabilities.

Density Matrix Analysis and Simulation of Electronic Excitations in Conjugated and Aggregated Molecules

“…Conjugated polymers have large polarizabilities attributed to the delocalized nature of electronic excitations. Numerous experimental and theoreticalstudies have forged a pretty good understanding of their electronic and optical characteristics. , Pioneering theoretical investigations of NLO properties of polymers using solid-state physical concepts have been carried out by André, Champagne, and co-workers − These investigations utilized the sum over states 273 and the polarization propagator technique. , A similar study has been done by using a variational method for the time-dependent wave function. , Ab initio approach combined CPHF method has been applied to polyene oligomers of moderate sizes, , extrapolated to the infinite systems using the periodic boundary conditions, , and extended into finite frequency off-resonant regime. − It has been shown that vibrational contributions to the polarizability may be as important as their electronic counterparts. − These nuclear effects arise from geometry deformations induced by the external field π-electron delocalization and polymer nonrigid energy potential surface strongly enhances the vibrational contribution.…”

“…Numerous experimental and theoretical studies have forged a pretty good understanding of their electronic and optical characteristics. 15,31 Pioneering theoretical investigations of NLO properties of polymers using solid-state physical concepts have been carried out by Andre ´, Champagne, and coworkers [272][273][274][275][276] These investigations utilized the sum over states 273 and the polarization propagator technique. 274,276 A similar study has been done by using a variational method for the time-dependent wave function.…”

The metal-insulator transition in dimerized Hückel chains

“…The Huckel polarizability for linear and alternate polyene chains was studied some years ago, for instance, by Champagne and André 19 and Davies. The Huckel polarizability for linear and alternate polyene chains was studied some years ago, for instance, by Champagne and André 19 and Davies.…”

Large nonlinear optical rectification in atomic hexagonal layers with broken space inversion symmetry

“…Note that this approach is now generally accepted in most of the theoretical treatments of the second-order NLO processes associated with electron motion in translation-invariant systems (see, e.g.,[35,36,[42][43][44][45]). …”