title: General Force-Field Parametrization Scheme for Molecular Dynamics Simulations of Conjugated Materials in Solution.
abstract: We describe a general scheme to obtain force-field parameters for classical molecular dynamics simulations of conjugated polymers. We identify a computationally inexpensive methodology for calculation of accurate intermonomer dihedral potentials and partial charges. Our findings indicate that the use of a two-step methodology of geometry optimization and single-point energy calculations using DFT methods produces potentials which compare favorably to high level theory calculation. We also report the effects of varying the conjugated backbone length and alkyl side-chain lengths on the dihedral profiles and partial charge distributions and determine the existence of converged lengths above which convergence is achieved in the force-field parameter sets. We thus determine which calculations are required for accurate parametrization and the scope of a given parameter set for variations to a given molecule. We perform simulations of long oligomers of dioctylfluorene and hexylthiophene in explicit solvent and find peristence lengths and end-length distributions consistent with experimental values.
authors.affiliation: Institute for Photonics and Quantum Sciences, School of Engineering and Physical Sciences, SUPA and ‡Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University , Edinburgh EH14 4AS, United Kingdom.
authors.forename: Jack
authors.initials: J
authors.lastname: Wildman
authors.affiliation: Institute for Photonics and Quantum Sciences, School of Engineering and Physical Sciences, SUPA and ‡Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University , Edinburgh EH14 4AS, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Repiščák
authors.affiliation: Institute for Photonics and Quantum Sciences, School of Engineering and Physical Sciences, SUPA and ‡Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University , Edinburgh EH14 4AS, United Kingdom.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Paterson
authors.affiliation: Institute for Photonics and Quantum Sciences, School of Engineering and Physical Sciences, SUPA and ‡Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University , Edinburgh EH14 4AS, United Kingdom.
authors.forename: Ian
authors.initials: I
authors.lastname: Galbraith