Electronic and vibrational polarizability and first hyperpolarizability of charge transfer chromophores: Quantum chemistry investigation

Issue title: Computational aspects of electric polarizability calculations: Atoms, Molecules and clusters, Part I

Article type: Research Article

Authors: Saal, Amar | Ouamerali, Ourida^{; *}

Affiliations: Laboratory of Physico-Chimie Théorique et de Chimie Informatique, Faculty of Chemistry USTHB-University, Algiers, Algeria

Correspondence: [*] Corresponding author. E-mail: [email protected].

Abstract: Static vibrational and electronic contributions to the longitudinal polarizability (α) and first hyperpolarizability (β) have been calculated, within the double harmonic oscillator approximation, at the HF/6-31G for a set of polyconjugated, D-linker-A, compounds. Effects due to the nature of the linker and of the D/A-pair type, on the geometrical structures and the electrical properties, are investigated. It turns out that, for a given linker, in almost all cases, the static βLe (0) and βLv (0) vary in the same order, with the type of the acceptor group A (A # NO2, COH, CF3). As well, the pair HO/NO2 was associated the greatest βLe(0) and βLv(0) values. The analysis upon the SOM expressions, due to Bishop and Kirtman, demonstrates that, more than 50% of βLv owes to three, two or even to only one vibrational normal mode contribution. Moreover, the vibrational modes with frequencies at, or more than, 3000 cm−1 present a null individual vibrational first hyperpolarizability.

Keywords: Polarizability, hyperpolarizability, vibrational contribution, ab-initio

DOI: 10.3233/JCM-2004-4310

Journal: Journal of Computational Methods in Sciences and Engineering, vol. 4, no. 3, pp. 333-344, 2004