title: Calculation and measurement of terahertz active normal modes in crystalline PETN.
abstract: The terahertz frequency spectrum of pentaerythritol tetranitrate (PETN) is calculated using Discover with the COMPASS force field, CASTEP and PWscf. The calculations are compared to each other and to terahertz spectra (0.3-3 THz) of crystalline PETN recorded at 4 K. A number of analysis methods are used to characterise the calculated normal modes.
authors.affiliation: School of Electronic and Electrical Engineering, Institute of Microwaves and Photonics, University of Leeds, Leeds, LS2 9JT, UK. A.D.Burnett@leeds.ac.uk
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Burnett
authors.forename: John
authors.initials: J
authors.lastname: Kendrick
authors.forename: John E
authors.initials: JE
authors.lastname: Cunningham
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hargreaves
authors.forename: Tasmin
authors.initials: T
authors.lastname: Munshi
authors.forename: Howell G M
authors.initials: HG
authors.lastname: Edwards
authors.forename: Edmund H
authors.initials: EH
authors.lastname: Linfield
authors.forename: A Giles
authors.initials: AG
authors.lastname: Davies
mesh_terms: D003460:Crystallization; D008958:Models, Molecular; D015394:Molecular Structure; D010417:Pentaerythritol Tetranitrate / Q000737:chemistry*; D011409:Propylene Glycols / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature; D055068:Terahertz Spectroscopy / Q000379:methods*; D013816:Thermodynamics
chemical_list: D011409:Propylene Glycols; D010417:Pentaerythritol Tetranitrate; C008783:pentaerythritol