Properties of Conjugated Materials from Quantum Chemistry Coupled to Molecular Dynamics Generated Ensembles.

ABSTRACT

We provide a set of molecular dynamics simulations employing a force field specifically parameterized for organic π-conjugated materials. The resulting conformation ensemble was coupled to quantum chemistry calculations, and quantities of interest for optoelectronic applications, namely, ground- and excited-state energies, oscillator strengths, and dipole moments were extracted. This combined approach allowed not only exploration of the configurational landscape but also of the resulting electronic properties of each frame within the simulation and thus probe the link between conformation and property. A study was made of the sampling and convergence requirements to yield reliable averages over the ensemble. Typically between 800 and 1000 conformations were sufficient to ensure convergence of properties. However, for some oligomers, more configurations were required to achieve convergence of the oscillator strength and magnitude of the dipole moment.