The longitudinal component of the dynamic electronic first hyperpolarizability of α,ω-nitro,amino-polyacetylene oligomers containing a small number of unit cells has been computed at the Hartree-Fock, Møller-Plesset and coupled-cluster levels with different atomic basis sets. Using frequency-dependent coupled-cluster results, we have tested the efficiency of the additive and multiplicative corrections to approximate the frequency-dependent correlated values. The multiplicative approach provides frequency-dependent electronic first hyperpolarizability values that are within a few percent of the true correlated ones whereas the additive correction leads to βL(-ωσ;ω1,ω 2) too small by ~20%. It turns out that the MP2/6-31G procedure is a suitable approach to reach a semi-quantitative accuracy.
|Pages (de - à)||327-334|
|Nombre de pages||8|
|journal||Chemical Physics Letters|
|Numéro de publication||3-4|
|Etat de la publication||Publié - 17 mars 2000|