Phonon dispersion of acene molecular crystals using van der Waals-corrected density functional theory

ORAL

Abstract

Acene molecular crystals are interesting testbeds for the study of phenomena relevant to organic optoelectronics, including charge separation and carrier transport. In such processes, scattering from lattice vibrations is an important dissipation mechanism. Despite their central role in dissipation processes, there are few calculations of phonon spectra in acene crystals. Here, we carry out van der Waals-corrected density functional theory calculations of the ground-state structure and phonon band structure of acene molecular crystals, comparing to neutron diffraction data where applicable. We use a finite-differences method, and compare the performance of several approaches -- including standard generalized gradient approximations (GGA) such as PBE, PBE plus pair-wise vdW corrections, and vdW density functionals -- to experiments for solid naphthalene and pentacene.

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Authors

  • Florian Altvater

    University of California, Berkeley

  • Tonatiuh Rangel

    Molecular Foundry, LBNL, Lawrence Berkeley National Laboratory

  • Jeffrey Neaton

    Univ of California - Berkeley, Molecular Foundry, Lawrence Berkeley National Laboratory, Physics Department, UC Berkeley \& Molecular Foundry, LBNL \& Kavli Energy NanoSciences Institute at Berkeley, Berkeley, University of California at Berkeley, University of California, Berkeley; Lawrence Berkeley National Laboratory, Dept. of Physics, UC Berkeley, Molecular Foundry, Lawrence Berkeley National Laboratory; Department of Physics, University of California-Berkeley, University of California, Berkeley and Lawrence Berkeley National Lab, Molecular Foundry, Lawrence Berkeley National Laboratory, and Department of Physics, UC-Berkeley, Lawrence Berkeley National Laboratory