Dynamics of dipolar molecular chains: from low excitations to soliton formation and classical chaotic dynamics

We investigate the classical rotational dynamics of a one- dimensional chain of molecules with permanent electric dipole moments. The molecules are coupled via their dipolar interactions. Low excitations are studied by inspecting the first- and second- order perturbation terms away from the equilibrium position. In this regime, we find no sign of localized excitations ( solitons). In the strong excitation ( rotary) regime, the classical dynamics is found to be chaotic. For this case, we calculate the time- correlation functions and estimate the Kolmogorov entropy as well as the fractal dimension. In addition, thermodynamical properties are discussed. In the second part of this work, we propose a method for exciting controllably the dipoles by means of a static electric field and a linear polarized, single- mode laser pulse. In the presence of external fields, we study the excitation propagation dynamics in the chain. As a function of the properties of the applied fields ( strengths, frequency and pulse duration), we inspect the non- stationary solutions and identify the solitonic, the breather and the classical chaotic regimes as well as where nonlinear resonances emerge.