We present a theoretical calculation, within a continuum electron-phonon-coupled model, of the optical absorption due to polarons in polyacetylene [{CH),]. Our results can be applied to both transand cis-(CH)„, as well as potentially to other polymers (polypyroles, polyparaphenylenes) in which polarons are present. We establish that the essential signature of polaron absorption is the existence...

INTRODUCTION The fact that polyacetylene (PA) [C2H2]∞ is isoelectronic with polycarbonitrile (PCN) [CHNH]∞ has caused many theoretical studies to investigate the later compound in diverse levels of theories, but using a fully trans structure [1], since this is the most stable structure for PA. More recent studies of the structural and thermodynamic stability using PCN in fully trans, cis-transo...

The intermediate neglect of differential overlap (INDO) band structures of polythiophene, polyfuran, and polypyrrole are analyzed in terms of the band structure of polyacetylene. This is done by decoupling the INDO Fock operator to obtain the band structure of the carbon system and of the heteroatoms. For all three polymer systems, the highest valence band is essentially a pure carbon band, whe...

Background and objectives: The aerial parts of Echinophora platyloba are added to cheese and yoghurt for flavoring. Besides, it is used for the treatment of flatulence and as air freshener. Despite several pharmacological studies on the plant, no attempt has been made to isolate non-volatile secondary metabolites from this plant. So, phytochemical investigation seems t...