A first-principles study of the vibrational properties of crystalline tetracene under pressure.
Author(s)
Abdulla, M
Refson, K
Friend, RH
Haynes, PD
Type
Journal Article
Abstract
We present a comprehensive study of the hydrostatic pressure dependence of the vibrational properties of tetracene using periodic density-functional theory (DFT) within the local density approximation (LDA). Despite the lack of van der Waals dispersion forces in LDA we find good agreement with experiment and are able to assess the suitability of this approach for simulating conjugated organic molecular crystals. Starting from the reported x-ray structure at ambient pressure and low temperature, optimized structures at ambient pressure and under 280 MPa hydrostatic pressure were obtained and the vibrational properties calculated by the linear response method. We report the complete phonon dispersion relation for tetracene crystal and the Raman and infrared spectra at the centre of the Brillouin zone. The intermolecular modes with low frequencies exhibit high sensitivity to pressure and we report mode-specific Grüneisen parameters as well as an overall Grüneisen parameter [Formula: see text]. Our results suggest that the experimentally reported improvement of the photocurrent under pressure may be ascribed to an increase in intermolecular interactions as also the dielectric tensor.
Date Issued
2015-09-02
Date Acceptance
2015-08-04
Citation
Journal of Physics: Condensed Matter, 2015, 27 (37), pp.375402-375402
ISSN
0953-8984
Publisher
IOP Publishing
Start Page
375402
End Page
375402
Journal / Book Title
Journal of Physics: Condensed Matter
Volume
27
Issue
37
Copyright Statement
©2015 IOP Publishing Ltd.
Subjects
hydrostatic pressure
vibrational properties
organic crystals
tetracene
Raman spectra
infrared spectra
phonons
Publication Status
Published