Ab initio dynamic polarizabilities of polymers. I. Hydrogen chain models

Abstract

mAb initio dynamic polarizabilities per unit cell of infinite stereoregular molecular hydrogen chains are calculated at the coupled Hartree -Fock level of approximation by using the random-phase approximation and the STO-3c and double-zeta atomic basis sets. Comparison with molecular calculations on increasingly large oligomeric chains emphasizes the nice extrapolation property of the polymeric technique that provides asymptotic values very close to the largest oligomeric values. The poles of the polarization propagator associated with the electric dipole polarizability correspond to the singlet excitation energies. Comparisons are performed with other techniques that provide the band gap. 0 1996 John Wiley & Sons, Inc.

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.…”

“…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. 277,278 Ab initio approach combined CPHF method has been applied to polyene oligomers of moderate sizes, 34,35 extrapolated to the infinite systems using the periodic boundary conditions, 279,280 and extended into finite frequency off-resonant regime.…”

Calculation of ab initio dynamic hyperpolarizabilities of polymers

“…[23][24][25][26][27] Without claiming to give a complete list of references we mention here the use of the summation over states procedure, 23 which corresponds to the UCHF-level, and the more rigorous approach based on the polarization propagator technique, 24,26 where in the randomphase approximation the reorganization of the electron distribution in the presence of the electric field is taken into account.…”