1
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Akaike K, Hosokai T, Ono Y, Tsuruta R, Yamada Y. Spontaneous orientation polarization of flavonoids. Sci Rep 2023; 13:19402. [PMID: 37938644 PMCID: PMC10632337 DOI: 10.1038/s41598-023-46834-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 11/06/2023] [Indexed: 11/09/2023] Open
Abstract
Spontaneous orientation polarization (SOP) is macroscopic electric polarization that is attributed to a constant orientational degree of dipole moments of polar molecules on average. The phenomenon has been found in small molecules like H2O at low temperatures and π-conjugated molecules employed in organic light-emitting diodes. In this study, we demonstrate that a thin film of baicalein, a flavonoid compound found in natural products, exhibits SOP and resultant giant surface potential (GSP) exceeding 5500 mV at a film thickness of 100 nm. Vacuum-deposition of baicalein under high vacuum results in smooth and amorphous films, which enables the generation of GSP with a slope of 57 mV/nm in air, a value comparable to the representative of an organic semiconductor showing GSP, tris(8-hydroxyquinoline)aluminum(III) (Alq3). We also found the superior photostability of a baicalein film compared to an Alq3 film. These findings highlight the potential of baicalein in new applications to organic electronics.
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Affiliation(s)
- Kouki Akaike
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology, Central 5, Higashi 1-1-1, Tsukuba, 305-8565, Japan.
| | - Takuya Hosokai
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Central 5, Higashi 1-1-1, Tsukuba, 305-8565, Japan
| | - Yutaro Ono
- Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8573, Japan
| | - Ryohei Tsuruta
- Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8573, Japan
| | - Yoichi Yamada
- Institute of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8573, Japan
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2
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Cassidy A, Pijpers FP, Field D. Hidden singularities in spontaneously polarized molecular solids. J Chem Phys 2023; 158:144501. [PMID: 37061481 DOI: 10.1063/5.0138642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023] Open
Abstract
Films of dipolar molecules formed by physical vapor deposition are, in general, spontaneously polarized, with implications ranging from electron transfer in molecular optoelectronic devices to the properties of astrochemical ices in the interstellar medium. Polarization arises from dipole orientation, which should intuitively decrease with increasing deposition temperature, T. However, it is experimentally found that minimum or maximum values in polarization vs T may be observed for cis-methyl formate, 1-propanol, and ammonia. A continuous analytic form of polarization vs T is developed, which has the property that it is not differentiable at all T. The minima and maxima in polarization vs T are marked by singularities in the differential of this analytic form. This exotic behavior is presently unique to films of dipolar species and has not been reported, for example, in the related magnetic phases of spin glasses.
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Affiliation(s)
- Andrew Cassidy
- Center for Interstellar Catalysis, Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Frank P Pijpers
- Korteweg - de Vries Institute for Mathematics, University of Amsterdam, Amsterdam, Netherlands
| | - David Field
- Center for Interstellar Catalysis, Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
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3
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Low-Energy Electron Generation for Biomolecular Damage Inquiry: Instrumentation and Methods. BIOPHYSICA 2022. [DOI: 10.3390/biophysica2040041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Technological advancement has produced a variety of instruments and methods to generate electron beams that have greatly assisted in the extensive theoretical and experimental efforts devoted to investigating the effect of secondary electrons with energies approximately less than 100 eV, which are referred as low-energy electrons (LEEs). In the past two decades, LEE studies have focused on biomolecular systems, which mainly consist of DNA and proteins and their constituents as primary cellular targets of ionizing radiation. These studies have revealed that compared to other reactive species produced by high-energy radiation, LEEs have distinctive pathways and considerable efficiency in inducing lethal DNA lesions. The present work aims to briefly discuss the current state of LEE production technology and to motivate further studies and improvements of LEE generation techniques in relation to biological electron-driven processes associated with such medical applications as radiation therapy and cancer treatment.
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4
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Hashemi SR, McCoustra MRS, Fraser HJ, Nyman G. A theoretical study on spontaneous dipole orientation in ice structures. Phys Chem Chem Phys 2022; 24:12922-12925. [PMID: 35593329 DOI: 10.1039/d2cp00360k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spontaneous dipole orientation is studied for a set of simulated porous ASW ice films on a substrate held at temperatures ranging from 10 K to 140 K. It is found that the water dipoles in the films obtained at the lower temperatures are oriented such that a negative electric field with a magnitude of 108-109 V m-1 is obtained. The magnitude of the field increases approximately linearly with height above the substrate, akin to experimental observations, although the magnitude of our field increases faster. A strong temperature dependence of the surface potential resulting from the spontelectric field is found, where the surface potential decreases when the substrate temperature increases. The surface potential finally becomes close to zero for temperatures around and above 110 K.
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Affiliation(s)
- S Rasoul Hashemi
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
| | | | - Helen J Fraser
- School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
| | - Gunnar Nyman
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
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5
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Sub-Hz Differential Rotational Spectroscopy of Enantiomers. Symmetry (Basel) 2021. [DOI: 10.3390/sym14010028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We demonstrate for the first time high-precision differential microwave spectroscopy, achieving sub-Hz precision by coupling a cryogenic buffer gas cell with a tunable microwave Fabry–Perot cavity. We report statistically limited sub-Hz precision of (0.08 ± 0.72) Hz, observed between enantiopure samples of (R)-1,2-propanediol and (S)-1,2-propanediol at frequencies near 15 GHz. We confirm highly repeatable spectroscopic measurements compared to traditional pulsed-jet methods, opening up new capabilities in probing subtle molecular structural effects at the 10−10 level and providing a platform for exploring sources of systematic error in parity-violation searches. We discuss dominant systematic effects at this level and propose possible extensions of the technique for higher precision.
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6
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Cassidy A, Jørgensen MRV, Glavic A, Lauter V, Plekan O, Field D. Low temperature aging in a molecular glass: the case of cis-methyl formate. Phys Chem Chem Phys 2021; 23:15719-15726. [PMID: 34279530 DOI: 10.1039/d1cp01332g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Glassy films of cis-methyl formate show spontaneous dipole orientation on deposition from the vacuum, the so-called 'spontelectric effect', creating surface potentials and electric fields within the films. We follow the decay of these fields, and their accompanying dipole orientation, on the hours timescale at deposition temperatures between 40 K and 55 K. Our data trace the low temperature 'secondary decay' mechanism, at tens of degrees below the glass transition temperature of 90 K. We show that secondary decay is due to molecular rotation, with associated activation energies lying between 0.1 and 0.2 eV. Diffusion is absent, as established from published neutron reflectivity data. Using an analytical model for the spontelectric effect, data are placed on a quantitative footing, showing that angular motion in excess of 50° reproduces the observed values of activation energies. Exploitation of the spontelectric effect is new in the study of glass aging and is shown here to give insight into the elusive processes which take place far from the molecular glass transition temperature.
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Affiliation(s)
- Andrew Cassidy
- Center for Interstellar Catalysis and Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C, Denmark.
| | - Mads R V Jørgensen
- Center of Materials Crystallography, iNano & Department of Chemistry, Aarhus University, Langelandsgade 140, Aarhus C, Denmark and MAX IV Laboratory, Lund University, Fotongatan 2, Lund, Sweden
| | - Artur Glavic
- Laboratory for Neutron and Muon Instrumentation, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Valeria Lauter
- Neutron Scattering Division, Oak Ridge National Lab, Oak Ridge, TN 37831, USA
| | - Oksana Plekan
- Sincrotrone Trieste S.C.P.A., Area Science Park, Strada Statale 14, km 163.5, I-34149 Basovizza, Trieste, Italy
| | - David Field
- Center for Interstellar Catalysis and Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C, Denmark.
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7
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Field D, Cassidy A. Comment on "Spontaneous Polarization of Cryo-Deposited Films for Five Normal Saturated Monohydroxy Alcohols, C nH 2n+1OH, n = 1-5". J Phys Chem B 2021; 125:7568-7569. [PMID: 34185522 DOI: 10.1021/acs.jpcb.1c02361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David Field
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus 8000 C, Denmark
| | - Andrew Cassidy
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus 8000 C, Denmark
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8
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Tourlakis GM, Adamopoulos SAT, Gavra IK, Milpanis AA, Tsagri LF, Pachygianni ASG, Chatzikokolis SS, Tsekouras AA. Sign flipping of spontaneous polarization in vapour-deposited films of small polar organic molecules. Phys Chem Chem Phys 2021; 23:14352-14362. [PMID: 34169950 DOI: 10.1039/d1cp01584b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Films of polar molecules vapour-deposited on sufficiently cold substrates are not only amorphous, but also exhibit charge polarization across their thickness. This is an effect known for 50 years, but it is very poorly understood and no mechanism exists in the literature that can explain and predict it. We investigated this bulk effect for 18 small organic molecules as a function of substrate temperature (30-130 K). We found that, as a rule, alcohol films have the negative end on the vacuum side at all temperatures. Alkyl acetates and toluene showed positive voltages which reached a maximum around the middle of the temperature range investigated. Tetrahydrofuran showed positive voltages which dropped with increasing deposition temperature. Diethyl ether, acetone, propanal, and butanal showed positive film voltages at low temperatures, negative at intermediate temperatures and again positive voltages at higher temperatures. In all cases, film voltages were monitored during heating leading to film evaporation. Film voltages were irreversibly eliminated before film elimination, but voltage profiles during temperature ramps differed vastly depending on compound and deposition temperature. In general, there was a gradual voltage reduction, but propanal, butanal, and diethyl ether showed a change in voltage sign during temperature ramp in films deposited at low temperatures. All these data expand substantially the experimental information regarding spontaneous polarization in vapour-deposited films, but still require complementary measurements as well as numerical simulations for a detailed explanation of the phenomenon.
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Affiliation(s)
- Georgios M Tourlakis
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Sotirios Alexandros T Adamopoulos
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Irini K Gavra
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Alexandros A Milpanis
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Liveria F Tsagri
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Aikaterini Sofia G Pachygianni
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Stylianos S Chatzikokolis
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
| | - Athanassios A Tsekouras
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, GR-15784, Greece.
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9
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Cassidy A, James RL, Dawes A, Field D. Crystallites and Electric Fields in Solid Ammonia. ChemistryOpen 2020; 9:983-990. [PMID: 33024652 PMCID: PMC7528761 DOI: 10.1002/open.202000118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/03/2020] [Indexed: 11/12/2022] Open
Abstract
Absorption spectra of vacuum-deposited films of ammonia have been obtained in the range 115 nm to 310 nm for a set of 15 deposition temperatures, Td, between 20 K and 80 K. Results focus upon the region 115 nm to 130 nm in overlapping D, E, F and G←X Rydberg transitions involving Wannier-Mott excitons. We identify two phases of ammonia, showing the solid to be polymorphic. Peak absorption wavelengths in the region of interest are found to shift to the red by 299 cm-1, for Td between 20 K to 50 K, and 1380 cm-1 for Td between 55 K to 80 K. Shifts provide evidence for the presence of spontaneously generated electric fields in these films, of values in excess of 108 V m-1 for Td of 20 K to 50 K to a few times 107 V m-1 for 55 K to 80 K. Results enable us to place a lower limit of 1.58 nm on the size of crystallites in the low temperature regime. This dimension represents 16 unit cells or 64 species, giving a more quantitative description than the nebulous term amorphous, as applied to solid ammonia. We also determine that crystallites formed in the high temperature regime contain, within ±20 %, 1688, 756 and 236 molecules of ammonia, respectively at Td of 65 K, 60 K and 55 K.
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Affiliation(s)
- Andrew Cassidy
- Department of Physics and AstronomyAarhus UniversityNy Munkegade 1208000AarhusDenmark
| | - Rachel L. James
- School of Physical SciencesThe Open UniversityWalton HallMilton KeynesMK7 6AAUK
| | - Anita Dawes
- School of Physical SciencesThe Open UniversityWalton HallMilton KeynesMK7 6AAUK
| | - David Field
- Department of Physics and AstronomyAarhus UniversityNy Munkegade 1208000AarhusDenmark
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10
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Hama T, Ishibashi A, Kouchi A, Watanabe N, Shioya N, Shimoaka T, Hasegawa T. Quantitative Anisotropic Analysis of Molecular Orientation in Amorphous N 2O at 6 K by Infrared Multiple-Angle Incidence Resolution Spectrometry. J Phys Chem Lett 2020; 11:7857-7866. [PMID: 32894947 DOI: 10.1021/acs.jpclett.0c01585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The existence of molecular orientational order in nanometer-thick films of molecules has long been implied by surface potential measurements. However, direct quantitative determination of the molecular orientation is challenging, especially for metastable amorphous thin films at low temperatures. This study quantifies molecular orientation in amorphous N2O at 6 K using infrared multiple-angle incidence resolution spectrometry (IR-MAIRS). The intensity ratio of the weak antisymmetric stretching vibration band of the 14N15NO isotopomer between the in-plane and out-of-plane IR-MAIRS spectra provides an average molecular orientation angle of 65° from the surface normal. No discernible change is observed in the orientation angle when a different substrate material is used (Si and Ar) at 6 K or the Si substrate temperature is changed in the range of 6-14 K. This suggests that the transient mobility of N2O during physisorption is key in governing the molecular orientation in amorphous N2O.
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Affiliation(s)
- Tetsuya Hama
- Komaba Institute for Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan
- Department of Basic Science, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan
| | - Atsuki Ishibashi
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Akira Kouchi
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Naoki Watanabe
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Nobutaka Shioya
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takafumi Shimoaka
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Takeshi Hasegawa
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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11
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Field D. Librating dipoles as a probe of spontaneously electrical films and as a source of THz radiation. Phys Chem Chem Phys 2019; 21:26606-26614. [DOI: 10.1039/c9cp05746c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pulsing a spontaneously electrical solid causes the molecular dipoles to oscillate and emit THz radiation.
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Affiliation(s)
- D. Field
- Department of Physics and Astronomy
- University of Aarhus
- Aarhus
- Denmark
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12
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Cassidy A, James RL, Dawes A, Lasne J, Field D. The optical absorption spectra of spontaneously electrical solids: the case of nitrous oxide. Phys Chem Chem Phys 2019; 21:1190-1197. [DOI: 10.1039/c8cp05746j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mud flats, Fejø, Denmark: a 2D representation of defect-free regions in a molecular crystal that can support Wannier–Mott excitons.
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Affiliation(s)
- Andrew Cassidy
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus
- Denmark
| | - Rachel L. James
- School of Physical Sciences
- The Open University
- Milton Keynes
- UK
| | - Anita Dawes
- School of Physical Sciences
- The Open University
- Milton Keynes
- UK
| | - Jérôme Lasne
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA)
- CNRS UMR 7583
- Universités Paris-Est Créteil and Paris Diderot
- 94010 Créteil cedex
- France
| | - David Field
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus
- Denmark
- ISA
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13
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Roman M, Dunn A, Taj S, Keolopile ZG, Rosu-Finsen A, Gutowski M, McCoustra MRS, Cassidy AM, Field D. Assigning a structural motif using spontaneous molecular dipole orientation in thin films. Phys Chem Chem Phys 2018; 20:29038-29044. [DOI: 10.1039/c8cp06010j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Guided by the spontelectric behaviour of thin films of cis-methyl formate, infrared observations and computational investigations reveal the dimer structural motif of the crystalline solid.
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Affiliation(s)
- M. Roman
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - A. Dunn
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - S. Taj
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - Z. G. Keolopile
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
- Department of Physics
| | - A. Rosu-Finsen
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - M. Gutowski
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | | | - A. M. Cassidy
- Department of Physics and Astronomy
- University of Aarhus
- Aarhus
- Denmark
| | - D. Field
- Department of Physics and Astronomy
- University of Aarhus
- Aarhus
- Denmark
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14
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Roman M, Taj S, Gutowski M, McCoustra MRS, Dunn AC, Keolopile ZG, Rosu-Finsen A, Cassidy AM, Field D. Non-linear and non-local behaviour in spontaneously electrical solids. Phys Chem Chem Phys 2018; 20:5112-5116. [DOI: 10.1039/c7cp08489g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We show that solids displaying spontaneous dipole orientation possess quite general non-local and non-linear characteristics expressed through their internal electric fields.
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Affiliation(s)
- M. Roman
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - S. Taj
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - M. Gutowski
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | | | - A. C. Dunn
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - Z. G. Keolopile
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - A. Rosu-Finsen
- Institute of Chemical Sciences
- Heriot-Watt University
- Edinburgh
- UK
| | - A. M. Cassidy
- Department of Physics and Astronomy
- University of Aarhus
- Aarhus
- Denmark
| | - D. Field
- Department of Physics and Astronomy
- University of Aarhus
- Aarhus
- Denmark
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15
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Chen YJ, Muñoz Caro GM, Aparicio S, Jiménez-Escobar A, Lasne J, Rosu-Finsen A, McCoustra MRS, Cassidy AM, Field D. Wannier-Mott Excitons in Nanoscale Molecular Ices. PHYSICAL REVIEW LETTERS 2017; 119:157703. [PMID: 29077429 DOI: 10.1103/physrevlett.119.157703] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Indexed: 06/07/2023]
Abstract
The absorption of light to create Wannier-Mott excitons is a fundamental feature dictating the optical and photovoltaic properties of low band gap, high permittivity semiconductors. Such excitons, with an electron-hole separation an order of magnitude greater than lattice dimensions, are largely limited to these semiconductors but here we find evidence of Wannier-Mott exciton formation in solid carbon monoxide (CO) with a band gap of >8 eV and a low electrical permittivity. This is established through the observation that a change of a few degrees K in deposition temperature can shift the electronic absorption spectra of solid CO by several hundred wave numbers, coupled with the recent discovery that deposition of CO leads to the spontaneous formation of electric fields within the film. These so-called spontelectric fields, here approaching 4×10^{7} V m^{-1}, are strongly temperature dependent. We find that a simple electrostatic model reproduces the observed temperature dependent spectral shifts based on the Stark effect on a hole and electron residing several nm apart, identifying the presence of Wannier-Mott excitons. The spontelectric effect in CO simultaneously explains the long-standing enigma of the sensitivity of vacuum ultraviolet spectra to the deposition temperature.
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Affiliation(s)
- Y-J Chen
- Department of Physics, National Central University, Jhongli District, Taoyuan City 32054, Taiwan
| | - G M Muñoz Caro
- Centro de Astrobiología (CSIC-INTA), Ctra. de Ajalvir, km 4, Torrejón de Ardoz, 28850 Madrid, Spain
| | - S Aparicio
- Instituto de Tecnologías Físicas y de la Información Leonardo Torres Quevedo, ITEFI (CSIC), c/Serrano 144, 28006 Madrid, Spain
| | - A Jiménez-Escobar
- INAF-Osservatorio Astronomico di Palermo, P.za Parlamento 1, 90134 Palermo, Italy
| | - J Lasne
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Universités Paris-Est Créteil and Paris Diderot, 61 avenue du Général de Gaulle, 94010 Créteil cedex, France Current address: IMT Lille Douai, Univ. Lille, SAGE-Département Sciences de l'Atmosphère et Génie de l'Environnement, 59000 Lille, France
| | - A Rosu-Finsen
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - M R S McCoustra
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - A M Cassidy
- Department of Physics and Astronomy, University of Aarhus, Aarhus DK-8000, Denmark
| | - D Field
- Department of Physics and Astronomy, University of Aarhus, Aarhus DK-8000, Denmark
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16
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Gavra IK, Pilidi AN, Tsekouras AA. Spontaneous polarization of vapor-deposited 1-butanol films and its dependence on temperature. J Chem Phys 2017; 146:104701. [DOI: 10.1063/1.4978239] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Irini K. Gavra
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos GR-15771, Greece
| | - Alexandra N. Pilidi
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos GR-15771, Greece
| | - Athanassios A. Tsekouras
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos GR-15771, Greece
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17
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Affiliation(s)
| | - Catherine Walsh
- Leiden
Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands
- School
of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
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18
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19
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Rosu-Finsen A, Lasne J, Cassidy A, McCoustra MRS, Field D. Spontaneous polarization of solid CO on water ices and some astrophysical implications. Phys Chem Chem Phys 2016; 18:5159-71. [DOI: 10.1039/c5cp07049j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reflection absorption infrared spectroscopy (RAIRS) is used to show that when 20 monolayer (ML) films of solid CO are laid down on solid water substrates at 20 to 24 K, the films polarize spontaneously.
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Affiliation(s)
| | - Jérôme Lasne
- Institute of Chemical Sciences
- Heriot-Watt University
- Riccarton
- UK
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA)
| | - Andrew Cassidy
- ISA
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C
- Denmark
| | | | - David Field
- ISA
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C
- Denmark
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20
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Bu C, Shi J, Raut U, Mitchell EH, Baragiola RA. Effect of microstructure on spontaneous polarization in amorphous solid water films. J Chem Phys 2015; 142:134702. [DOI: 10.1063/1.4916322] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Caixia Bu
- Laboratory for Atomic and Surface Physics, University of Virginia, Thornton Hall, Charlottesville, Virginia 22904, USA
| | - Jianming Shi
- Laboratory for Atomic and Surface Physics, University of Virginia, Thornton Hall, Charlottesville, Virginia 22904, USA
| | - Ujjwal Raut
- Laboratory for Atomic and Surface Physics, University of Virginia, Thornton Hall, Charlottesville, Virginia 22904, USA
| | - Emily H. Mitchell
- Laboratory for Atomic and Surface Physics, University of Virginia, Thornton Hall, Charlottesville, Virginia 22904, USA
| | - Raúl A. Baragiola
- Laboratory for Atomic and Surface Physics, University of Virginia, Thornton Hall, Charlottesville, Virginia 22904, USA
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21
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Lasne J, Rosu-Finsen A, Cassidy A, McCoustra MRS, Field D. Spontaneous electric fields in solid carbon monoxide. Phys Chem Chem Phys 2015; 17:30177-87. [DOI: 10.1039/c5cp04536c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Reflection–absorption infrared spectroscopy (RAIRS) is shown to provide a means of observing the spontelectric phase of matter, the defining characteristic of which is the occurrence of a spontaneous and powerful static electric field within a film of material.
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Affiliation(s)
- Jérôme Lasne
- Institute of Chemical Sciences
- Heriot-Watt University
- Riccarton
- UK
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA)
| | | | - Andrew Cassidy
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C
- Denmark
| | | | - David Field
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C
- Denmark
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22
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Lasne J, Rosu-Finsen A, Cassidy A, McCoustra MRS, Field D. Spontaneously electrical solids in a new light. Phys Chem Chem Phys 2015. [DOI: 10.1039/c5cp03174e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Reflection–absorption infrared spectroscopy (RAIRS) of nitrous oxide (N2O) thin films is shown to provide an independent means of observing the spontelectric state; the first new structural phase of matter, with unique electrical properties, to have emerged in decades.
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Affiliation(s)
- Jérôme Lasne
- Institute of Chemical Sciences
- Heriot-Watt University
- Riccarton
- UK
| | | | - Andrew Cassidy
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C
- Denmark
| | | | - David Field
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C
- Denmark
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23
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Cassidy A, Plekan O, Balog R, Dunger J, Field D, Jones NC. Electric Field Structures in Thin Films: Formation and Properties. J Phys Chem A 2014; 118:6615-21. [DOI: 10.1021/jp503332x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew Cassidy
- Department of Physics and
Astronomy, Aarhus University, DK-8000 Aarhus
C, Denmark
| | - Oksana Plekan
- Department of Physics and
Astronomy, Aarhus University, DK-8000 Aarhus
C, Denmark
| | - Richard Balog
- Department of Physics and
Astronomy, Aarhus University, DK-8000 Aarhus
C, Denmark
| | - Jack Dunger
- Department of Physics and
Astronomy, Aarhus University, DK-8000 Aarhus
C, Denmark
| | - David Field
- Department of Physics and
Astronomy, Aarhus University, DK-8000 Aarhus
C, Denmark
| | - Nykola C. Jones
- ISA, Department of Physics
and Astronomy, Aarhus University, DK-8000 Aarhus
C, Denmark
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24
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Cassidy A, Plekan O, Dunger J, Balog R, Jones NC, Lasne J, Rosu-Finsen A, McCoustra MRS, Field D. Investigations into the nature of spontelectrics: nitrous oxide diluted in xenon. Phys Chem Chem Phys 2014; 16:23843-53. [DOI: 10.1039/c4cp03659j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The recent discovery of a new class of solids displaying bulk spontaneous electric fields as high as 108 V m−1, so-called ‘spontelectrics’, poses fundamental and unresolved problems in solid state physics.
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Affiliation(s)
- Andrew Cassidy
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C, Denmark
| | - Oksana Plekan
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C, Denmark
| | - Jack Dunger
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C, Denmark
| | - Richard Balog
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C, Denmark
| | - Nykola C. Jones
- ISA
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C, Denmark
| | - Jérôme Lasne
- Institute of Chemical Sciences
- Heriot-Watt University
- EH14 4AS Edinburgh, UK
| | | | | | - David Field
- Department of Physics and Astronomy
- Aarhus University
- DK-8000 Aarhus C, Denmark
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25
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Field D, Plekan O, Cassidy A, Balog R, Jones N, Dunger J. Spontaneous electric fields in solid films: spontelectrics☆. INT REV PHYS CHEM 2013. [DOI: 10.1080/0144235x.2013.767109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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26
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Cassidy A, Plekan O, Balog R, Jones NC, Field D. Spontaneous electric fields in films of CF3Cl, CF2Cl2and CFCl3. Phys Chem Chem Phys 2013; 15:108-13. [DOI: 10.1039/c2cp43138f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Plekan O, Cassidy A, Balog R, Jones NC, Field D. Spontaneous electric fields in films of cis-methyl formate. Phys Chem Chem Phys 2012; 14:9972-6. [DOI: 10.1039/c2cp41229b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Plekan O, Cassidy A, Balog R, Jones NC, Field D. A new form of spontaneously polarized material. Phys Chem Chem Phys 2011; 13:21035-44. [DOI: 10.1039/c1cp22310k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Vizcaino V, Denifl S, Märk TD, Illenberger E, Scheier P. Low energy (0-4 eV) electron impact to N(2)O clusters: Dissociative electron attachment, ion-molecule reactions, and vibrational Feshbach resonances. J Chem Phys 2010; 133:154512. [PMID: 20969408 DOI: 10.1063/1.3505143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Electron attachment to clusters of N(2)O in the energy range of 0-4 eV yields the ionic complexes [(N(2)O)(n)O](-), [(N(2)O)(n)NO](-), and (N(2)O)(n) (-) . The shape of the ion yields of the three homologous series differs substantially reflecting the different formation mechanisms. While the generation of [(N(2)O)(n)O](-) can be assigned to dissociative electron attachment (DEA) of an individual N(2)O molecule in the target cluster, the formation of [(N(2)O)(n)NO](-) is interpreted via a sequence of ion molecule reactions involving the formation of O(-) via DEA in the first step. The nondecomposed complexes (N(2)O)(n) (-) are preferentially formed at very low energies (below 0.5 eV) as a result of intramolecular stabilization of a diffuse molecular anion at low energy. The ion yields of [(N(2)O)(n)O](-) and (N(2)O)(n) (-) versus electron energy show sharp peaks at the threshold region, which can be assigned to vibrational Feshbach resonances mediated by the diffuse anion state as already observed in an ultrahigh resolution electron attachment study of N(2)O clusters [E. Leber, S. Barsotti, J. Bömmels, J. M. Weber, I. I. Fabrikant, M.-W. Ruf, and H. Hotop, Chem. Phys. Lett. 325, 345 (2000)].
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Affiliation(s)
- Violaine Vizcaino
- Institut für Ionenphysik und Angewandte Physik, Leopold Franzens-Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
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