Theoretical study of the longitudinal first hyperpolarizability of polysilaacetylene.
With the help of ab initio tools taking into account dynamic electron correlation effects, we study the longitudinal electronic first hyperpolarizability of carbon-silicon analogues to polyacetylene. It turns out that the MP2/6-31G(d)//HF/6-31G(d) scheme is suitable to obtain a semiquantitative accuracy for the first hyperpolarizability of long polysilaacetylene oligomers. The conformation of the chain has a crucial impact on its second-order nonlinear optical properties. We also show that, for some chain lengths, the frequency dispersion effects may have a huge impact, even when far away from resonance. These phenomena are rationalized in terms of delocalization and asymmetry.
Laboratoire de Chimie Theorique Appliquee, Facultes Universitaires Notre-Dame de la Paix, B-5000 Namur, Belgium. denis.jacquemin@fundp.ac.be
Denis
D
Jacquemin
Eric A
EA
Perpete
Jean-Marie
JM
Andre