A study of the vibrational spectra of two-dimensional polymers

Polyacetylene and polyaniline usually have one-dimensional character because their interchain coupling interaction is weak. As the pressure increases, the interaction also increases and interchain energy gap reduces so that interchain distance b decreases and interchain elastic distance increases. When b approaches the lattice constant a., the polymer of one-dimensional. chains becomes. a two-dimensional compound lattice structure after considering their interchain coupling action, and new physical properties may arise. In this paper, the second-nearest-neighbor interactions between lattice chains of polyacetylene. and polyaniline are considered, and the two-dimensional compound I lattice model is adopted. Using the method of lattice. dynamics, the dispersion curves of these polymers' under different mass ratio are calculated and three kinds of lattice chain interactions are also investigated. The changes of spectra in high symmetric curves under BZ are discussed. We also plot the curve under the various. mass ratios. The results show that the two-dimensional compound lattice polymer has two acoustic branches and two optical branches, and the increase of interchain coupling interaction can destroy the effects of aberration of dimerization, and cause the dimensional effect. If interchain coupling interaction is weak and vibration of interchain direction can be neglected, the polymer becomes one-dimensional chain and has only an optical branch and an acoustic branch.