Search or ask a question
Pricing
Login
Sign up
Home
Notebook
Profile
Citation booster
Literature Review
Copilot
Citation generator
Paraphraser
AI Detector
Chrome Extension
Talk with us
Use on ChatGPT
All figures (9)
Figure 6. (a) The average mode-specific Grüneisen parameter of tetracene crystal as a function of mode frequency for the intermolecular low frequency modes. (b) The modespecific Grüneisen parameter of tetracene crystal at as a function of mode frequency for the modes with frequencies below 600 cm -1 .
Figure 7. The Raman spectra of LT tetracene structure at ambient pressure conditions (solid line) and under hydrostatic pressure of 280MPa (dotted line).
Figure 2. Theoretically DFT-LDA calculated dispersion relations for LT tetracene along the principal symmetry directions and some other points in BZ along the path described in Figure 2. The intermolecular modes in (a) and (b) are at ambient pressure and under hydrostatic pressure of 280MPa, respectively. The intermolecular and low-laying intramolecular modes in (c) and (d) are at ambient pressure and under hydrostatic pressure of 280MPa, respectively. The high symmetry points of the BZ are labelled relative to the cell vectors according to reference [37].
Table 1. The DFT-LDA lattice parameters for tetracene computed at ambient and 280 MPa hydrostatic pressures together with those experimentally measured in Refs. [24] and [31]. The area of the ab plane is defined as (Aab =ab sin).
Table 2. Comparison of the frequencies of the intermolecular and some of the intramolecular infrared modes (in cm -1 ) calculated using DFT-LDA (this work) and reported experimental and theoretically calculated data from literature [52-56]. R denotes predicted Raman-active band.For complete infrared DFT-LDA calculated modes see supplementary information.
Figure 1. The structure of tetracene crystal at ambient pressure and a temperature of 175K. The image illustrates the stacking of the layers along the c-axis.
Figure 8. The infrared spectra of LT tetracene structure at ambient pressure conditions and under hydrostatic pressure of 280MPa.
Figure 5. Theoretically DFT-LDA calculated vibrational density of states for LT tetracene at ambient pressure and under hydrostatic pressure of 280MPa.
Table 3: The complete dielectric tensor together with the eigenvalues for the optical frequencies () and the low frequencies () for DFT-LDA optimised LT tetracene structure at ambient and 280MPa pressures. Also the dielectric Grüneisen parameter is shown. The Cartesian x-axis is taken to be along the crystal x-direction parallel to the lattice vector a.
Journal Article
•
DOI
•
A first-principles study of the vibrational properties of crystalline tetracene under pressure
[...]
Mayami Abdulla
1
,
Keith Refson
2
,
Keith Refson
3
,
Richard H. Friend
1
,
Peter D. Haynes
4
- Show less
+1 more
•
Institutions (4)
University of Cambridge
1
,
Royal Holloway, University of London
2
,
Rutherford Appleton Laboratory
3
,
Imperial College London
4
02 Sep 2015
-
Journal of Physics: Condensed Matter