The molecular structure and dynamics of the photoexcited metal-to-ligand-charge-transfer (MLCT) state of [Cu(I)(dmp)(2)](+), where dmp is 2,9-dimethyl-1,10-phenanthroline, in acetonitrile have been investigated by time-domain pump-probe X-ray absorption spectroscopy, femtosecond optical transient spectroscopy, and density functional theory (DFT). The time resolution for the excited state structural determination was 100 ps, provided by single X-ray pulses from a third generation synchrotron source. The copper ion in the thermally equilibrated MLCT state has the same oxidation state as the corresponding copper(II) complex in the ground state and was found to be penta-coordinate with an average nearest neighbor Cu-N distance 0.04 A shorter than that of the ground state [Cu(I)(dmp)(2)](+). The results confirm the previously proposed "exciplex" structure of the MLCT state in Lewis basic solvents. The evolution from the photoexcited Franck-Condon MLCT state to the thermally equilibrated MLCT state was followed by femtosecond optical transient spectroscopy, revealing three time constants of 500-700 fs, 10-20 ps, and 1.6-1.7 ns, likely related to the kinetics for the formation of the triplet MLCT state, structural relaxation, and the MLCT excited-state decay to the ground state, respectively. DFT calculations are used to interpret the spectral shift on structural relaxation and to predict the geometries of the ground state, the tetracoordinate excited state, and the exciplex. The DFT calculations also indicate that the amount of charge transferred from copper to the dmp ligand upon photoexcitation is similar to the charge difference at the copper center between the ground-state copper(I) and copper(II) complexes.

A d-dimensional second-order topological insulator (SOTI) can host topologically protected (d−2)dimensional gapless boundary modes. Here we show that a 2D non-Hermitian SOTI can host zero-energy modes at its corners. In contrast to the Hermitian case, these zero-energy modes can be localized only at one corner. A 3D non-Hermitian SOTI is shown to support second-order boundary modes, which are localized not along hinges but anomalously at a corner. The usual bulkcorner (hinge) correspondence in the second-order 2D (3D) non-Hermitian system breaks down. The winding number (Chern number) based on complex wavevectors is used to characterize the second-order topological phases in 2D (3D). A possible experimental situation with ultracold atoms is also discussed. Our work lays the cornerstone for exploring higher-order topological phenomena in non-Hermitian systems.arXiv:1810.04067v3 [cond-mat.mes-hall]

(2017) Surface-sensitive NMR detection of the solid electrolyte interphase layer on reduced graphene oxide. Journal of Physical Chemistry Letters, 8 (5). pp. 1078 -1085 . ISSN 1948 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/42184/1/Leskes%20et%20al.%20-%202017%20-%20Surface %20Sensitive%20NMR%20Detection%20of%20the%20SEI%20Layer%20on%20Reduced %20Graphene%20Oxide.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Just Accepted "Just Accepted" manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides "Just Accepted" as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. "Just Accepted" manuscripts appear in full in PDF format accompanied by an HTML abstract. "Just Accepted" manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). "Just Accepted" is an optional service offered to authors. Therefore, the "Just Accepted" Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the "Just Accepted" Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these "Just Accepted" manuscripts. 1Surface Sensitive NMR Detection of the SEI Layer on Reduced Graphene OxideMichal Leskes (1) *, Gunwoo Kim (2,3) , Tao Liu (2) , Alison L. Michan, (2) Fabien Aussenac (4) , Patrick Dorffer (4) , Subhradip Paul (5) , Clare P. Grey Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UKCambridge Graphene Centre, University of Cambridge, Cambridge, CB3 0FA, UKBruker BioSpin, 34 rue de l'Industrie BP 10002, 67166 Wissembourg Cedex, France 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1...

Conventional n-dimensional topological superconductors (TSCs) have protected gapless (n − 1)dimensional boundary states. In contrast to this, second-order TSCs are characterized by topologically protected gapless (n − 2)-dimensional states with usual gapped (n − 1)-boundaries.Here, we study a second-order TSC with a two-dimensional (2D) magnetic topological insulator (TI) proximity-coupled to a high-temperature superconductor, where Majorana bound states (MBSs) are localized at the corners of a square sample with gapped edge modes. Due to the mirror symmetry of the hybrid system considered here, there are two MBSs at each corner for both cases: d-wave and s±-wave superconducting pairing. We present the corresponding topological phase diagrams related to the role of the magnetic exchange interaction and the pairing amplitude. A detailed analysis, based on edge theory, reveals the origin of the existence of MBSs at the corners of the 2D sample, which results from the sign change of the Dirac mass emerging at the intersection of any two adjacent edges due to pairing symmetry. Possible experimental realizations are discussed. Our proposal offers a promising platform for realizing MBSs and performing possible non-Abelian braiding in 2D systems. arXiv:1806.07002v2 [cond-mat.mes-hall]

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The influence of temperature on the gold nanorod synthesis process and its effect on tailoring the size and aspect ratio have not been fully investigated and understood. A comprehensive study, involving SEM and TEM microscopy, Vis-NIR spectroscopy, quantitative data analysis and theoretical simulation, is performed to understand the effect of growth temperature on size, aspect ratio, and shape uniformity of gold nanorods that are synthesized by a recently developed binary-surfactant seed-mediated AuNR synthesis method. It has been demonstrated that the temperature can be used as a simple processing parameter to viably tailor the size and aspect ratio of AuNRs as well as the corresponding surface plasmon resonance behavior. The temperature coefficients for length, diameter, and aspect ratio have been, respectively, determined to be 3.5 nm/°C, 3.9 nm/°C, and -0.18/°C. With a combination of controlling temperature and formulation, the binary surfactant seed-mediated AuNR synthesis method expects to be a convenient way for producing gold nanorods with a large range of size and aspect ratio suitable for different applications.