title: Photochemistry of the α-Al₂O₃-PETN Interface.
abstract: Optical absorption measurements are combined with electronic structure calculations to explore photochemistry of an α-Al₂O₃-PETN interface formed by a nitroester (pentaerythritol tetranitrate, PETN, C₅H₈N₄O12) and a wide band gap aluminum oxide (α-Al₂O₃) substrate. The first principles modeling is used to deconstruct and interpret the α-Al₂O₃-PETN absorption spectrum that has distinct peaks attributed to surface F⁰-centers and surface-PETN transitions. We predict the low energy α-Al₂O₃ F⁰-center-PETN transition, producing the excited triplet state, and α-Al₂O₃ F⁰-center-PETN charge transfer, generating the PETN anion radical. This implies that irradiation by commonly used lasers can easily initiate photodecomposition of both excited and charged PETN at the interface. The feasible mechanism of the photodecomposition is proposed.
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA. rtsyshev@umd.edu.
authors.forename: Roman V
authors.initials: RV
authors.lastname: Tsyshevsky
authors.affiliation: Department of Organic and Physical Chemistry, Kemerovo State University, Kemerovo 650043, Russia. anthon.zverev@yandex.ru.|Yurga Institute of Technology, National Research Tomsk Polytechnic University, Yurga 652057, Russia. anthon.zverev@yandex.ru.
authors.forename: Anton
authors.initials: A
authors.lastname: Zverev
authors.affiliation: Department of Organic and Physical Chemistry, Kemerovo State University, Kemerovo 650043, Russia. anatoly.y.mitrofanov@gmail.com.|Yurga Institute of Technology, National Research Tomsk Polytechnic University, Yurga 652057, Russia. anatoly.y.mitrofanov@gmail.com.
authors.forename: Anatoly
authors.initials: A
authors.lastname: Mitrofanov
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA. rashkesn@yahoo.com.|Qatar Environment &amp; Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation, P.O. Box 5825, Doha, Qatar. rashkesn@yahoo.com.
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Rashkeev
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA. mkukla@nsf.gov.
authors.forename: Maija M
authors.initials: MM
authors.lastname: Kuklja
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D008958:Models, Molecular; D010417:Pentaerythritol Tetranitrate / Q000737:chemistry*; D055668:Photochemical Processes; D010777:Photochemistry
chemical_list: D010417:Pentaerythritol Tetranitrate; D000537:Aluminum Oxide
keywords: F-centers; decomposition barrier; electronically excited and charged state; explosives; initiation of detonation; oxygen vacancy; singlet-triplet exciton