@article{BelasriTopalHeydenreichetal.2020,
  author    = {Belasri, Khadija and Topal, Leila and Heydenreich, Matthias and Koch, Andreas and Kleinpeter, Erich and Fulop, Ferenc and Szatmari, Istvan},
  title     = {Synthesis and conformational analysis of naphthoxazine-fused phenanthrene derivatives},
  series = {Molecules},
  volume    = {25},
  journal   = {Molecules},
  number    = {11},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1420-3049},
  doi       = {10.3390/molecules25112524},
  pages     = {15},
  year      = {2020},
  abstract  = {The synthesis of new phenanthr[9,10-e][1,3]oxazines was achieved by the direct coupling of 9-phenanthrol with cyclic imines in the modified aza-Friedel-Crafts reaction followed by the ring closure of the resulting bifunctional aminophenanthrols with formaldehyde. Aminophenanthrol-type Mannich bases were synthesised and transformed to phenanthr[9,10-e][1,3]oxazines via [4 + 2] cycloaddition. Detailed NMR structural analyses of the new polyheterocycles as well as conformational studies including Density Functional Theory (DFT) modelling were performed. The relative stability of ortho-quinone methides (o-QMs) was calculated, the geometries obtained were compared with the experimentally determined NMR structures, and thereby, the regioselectivity of the reactions has been assigned.},
  language  = {en}
}
@article{EhlertKlamroth2020,
  author    = {Ehlert, Christopher and Klamroth, Tillmann},
  title     = {PSIXAS: A Psi4 plugin for efficient simulations of X-ray absorption spectra based on the transition-potential and Delta-Kohn-Sham method},
  series = {Journal of computational chemistry : organic, inorganic, physical, biological},
  volume    = {41},
  journal   = {Journal of computational chemistry : organic, inorganic, physical, biological},
  number    = {19},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0192-8651},
  doi       = {10.1002/jcc.26219},
  pages     = {1781 -- 1789},
  year      = {2020},
  abstract  = {Near edge X-ray absorption fine structure (NEXAFS) spectra and their pump-probe extension (PP-NEXAFS) offer insights into valence- and core-excited states. We present PSIXAS, a recent implementation for simulating NEXAFS and PP-NEXAFS spectra by means of the transition-potential and the Delta-Kohn-Sham method. The approach is implemented in form of a software plugin for the Psi4 code, which provides access to a wide selection of basis sets as well as density functionals. We briefly outline the theoretical foundation and the key aspects of the plugin. Then, we use the plugin to simulate PP-NEXAFS spectra of thymine, a system already investigated by others and us. It is found that larger, extended basis sets are needed to obtain more accurate absolute resonance positions. We further demonstrate that, in contrast to ordinary NEXAFS simulations, where the choice of the density functional plays a minor role for the shape of the spectrum, for PP-NEXAFS simulations the choice of the density functional is important. Especially hybrid functionals (which could not be used straightforwardly before to simulate PP-NEXAFS spectra) and their amount of "Hartree-Fock like" exact exchange affects relative resonance positions in the spectrum.},
  language  = {en}
}
@misc{EllisBauerBacigalupoetal.2018,
  author    = {Ellis, S. C. and Bauer, S. and Bacigalupo, C. and Bland-Hawthorn, J. and Bryant, J. J. and Case, S. and Content, R. and Fechner, T. and Giannone, D. and Haynes, R. and Hernandez, E. and Horton, A. J. and Klauser, U. and Lawrence, J. S. and Leon-Saval, S. G. and Lindley, E. and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Min, S. -S. and Pai, N. and Roth, M. and Shortridge, K. and Waller, L. and Xavier, Pascal and Zhelem, Ross},
  title     = {PRAXIS: an OH suppression optimised near infrared spectrograph},
  series = {Ground-based and Airborne Instrumentation for Astronomy VII},
  volume    = {10702},
  journal   = {Ground-based and Airborne Instrumentation for Astronomy VII},
  publisher = {SPIE-INT Soc Optical Engineering},
  address   = {Bellingham},
  isbn      = {978-1-5106-1958-6},
  issn      = {0277-786X},
  doi       = {10.1117/12.2311898},
  pages     = {16},
  year      = {2018},
  abstract  = {The problem of atmospheric emission from OH molecules is a long standing problem for near-infrared astronomy. PRAXIS is a unique spectrograph which is fed by fibres that remove the OH background and is optimised specifically to benefit from OH-Suppression. The OH suppression is achieved with fibre Bragg gratings, which were tested successfully on the GNOSIS instrument. PRAXIS uses the same fibre Bragg gratings as GNOSIS in its first implementation, and will exploit new, cheaper and more efficient, multicore fibre Bragg gratings in the second implementation. The OH lines are suppressed by a factor of similar to 1000, and the expected increase in the signal-to-noise in the interline regions compared to GNOSIS is a factor of similar to 9 with the GNOSIS gratings and a factor of similar to 17 with the new gratings. PRAXIS will enable the full exploitation of OH suppression for the first time, which was not achieved by GNOSIS (a retrofit to an existing instrument that was not OH-Suppression optimised) due to high thermal emission, low spectrograph transmission and detector noise. PRAXIS has extremely low thermal emission, through the cooling of all significantly emitting parts, including the fore-optics, the fibre Bragg gratings, a long length of fibre, and the fibre slit, and an optical design that minimises leaks of thermal emission from outside the spectrograph. PRAXIS has low detector noise through the use of a Hawaii-2RG detector, and a high throughput through a efficient VPH based spectrograph. PRAXIS will determine the absolute level of the interline continuum and enable observations of individual objects via an IFU. In this paper we give a status update and report on acceptance tests.},
  language  = {en}
}
@phdthesis{Haubitz2021,
  author    = {Haubitz, Toni},
  title     = {Transient absorption spectroscopy},
  doi       = {10.25932/publishup-53509},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-535092},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiii, 176},
  year      = {2021},
  abstract  = {The optical properties of chromophores, especially organic dyes and optically active inorganic molecules, are determined by their chemical structures, surrounding media, and excited state behaviors. The classical optical go-to techniques for spectroscopic investigations are absorption and luminescence spectroscopy. While both techniques are powerful and easy to apply spectroscopic methods, the limited time resolution of luminescence spectroscopy and its reliance on luminescent properties can make its application, in certain cases, complex, or even impossible. This can be the case when the investigated molecules do not luminesce anymore due to quenching effects, or when they were never luminescent in the first place. In those cases, transient absorption spectroscopy is an excellent and much more sophisticated technique to investigate such systems. This pump-probe laser-spectroscopic method is excellent for mechanistic investigations of luminescence quenching phenomena and photoreactions. This is due to its extremely high time resolution in the femto- and picosecond ranges, where many intermediate or transient species of a reaction can be identified and their kinetic evolution can be observed. Furthermore, it does not rely on the samples being luminescent, due to the active sample probing after excitation. In this work it is shown, that with transient absorption spectroscopy it was possible to identify the luminescence quenching mechanisms and thus luminescence quantum yield losses of the organic dye classes O4-DBD, S4-DBD, and pyridylanthracenes. Hence, the population of their triplet states could be identified as the competitive mechanism to their luminescence. While the good luminophores O4-DBD showed minor losses, the S4-DBD dye luminescence was almost entirely quenched by this process. However, for pyridylanthracenes, this phenomenon is present in both the protonated and unprotonated forms and moderately effects the luminescence quantum yield. Also, the majority of the quenching losses in the protonated forms are caused by additional non-radiative processes introduced by the protonation of the pyridyl rings. Furthermore, transient absorption spectroscopy can be applied to investigate the quenching mechanisms of uranyl(VI) luminescence by chloride and bromide. The reduction of the halides by excited uranyl(VI) leads to the formation of dihalide radicals X^(·-2). This excited state redox process is thus identified as the quenching mechanism for both halides, and this process, being diffusion-limited, can be suppressed by cryogenically freezing the samples or by observing these interactions in media with a lower dielectric constant, such as ACN and acetone.},
  language  = {en}
}
@phdthesis{Menski2019,
  author    = {Menski, Antonia Isabell},
  title     = {Europium als strukturelle Sonde zur Analyse neuartiger Materialien},
  doi       = {10.25932/publishup-42714},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427141},
  school      = {Universit{\"a}t Potsdam},
  pages     = {181},
  year      = {2019},
  abstract  = {Im Rahmen dieser Arbeit wird anhand von neuartigen Materialien das Potential der Europium-Lumineszenz f{\"u}r die strukturelle Analyse dargestellt. Bei diesen Materialien handelt es sich zum einen um Nanopartikel mit Matrizes aus mehreren Metall-Mischoxiden und Dotierungen durch die Sonde Europium und zum anderen um Metallorganische Netzwerke (MOFs), die mit Neodym , Samarium- und Europium-Ionen beladen sind. Die Synthese der aus der Kombination von Metalloxiden enthaltenen Nanopartikel ist unter milden Bedingungen mithilfe von speziell daf{\"u}r hergestellten Reagenzien erfolgt und hat zu sehr kleinen, amorphen Nanopartikeln gef{\"u}hrt. Durch eine nachfolgende Temperaturbehandlung hat sich die Kristallinit{\"a}t erh{\"o}ht. Damit verbunden haben sich auch die Kristallstruktur sowie die Position des Dotanden Europium ver{\"a}ndert. W{\"a}hrend die etablierte Methode der R{\"o}ntgendiffraktometrie einen Blick auf das Kristallgitter als Gesamtes erm{\"o}glicht, so trifft die Lumineszenz des Europiums durch die Sichtbarkeit einzelner Stark-Aufspaltungen Aussagen {\"u}ber dessen lokale Symmetrien. Die Symmetrie wird durch Sauerstofffehlstellen ver{\"a}ndert, welche die Sauerstoffleitf{\"a}higkeit der Nanopartikel beeinflussen. Diese ist f{\"u}r die Anwendung als Katalysatoren in industriellen Prozessen und ebenso als Sensoren und Therapeutika in biologischen Systemen von Bedeutung. Zur ersten katalytischen Charakterisierung werden die Proben mittels Temperatur-programmierter Reduktion untersucht. Des Weiteren werden die Mischoxid-Nanopartikel auch hinsichtlich ihrer Verwendbarkeit als Matrix in Aufkonversionsprozessen untersucht. Die Metallorganischen Netzwerke eignen sich aufgrund ihrer mikropor{\"o}sen Struktur f{\"u}r Anwendungen in der Speicherung gleichermaßen von Nutzgasen wie auch von Schadstoffen. Ebenfalls ist eine biologische Anwendung denkbar, die insbesondere den Bereich der drug delivery-Reagenzien betrifft. Erfolgt in die mikropor{\"o}sen Strukturen der Metallorganischen Netzwerke die Einlagerung von Lanthanoid-Ionen, so k{\"o}nnen diese bei der entsprechenden Kombination als Weißlicht-Emittierer fungieren. Dabei ist neben den Verh{\"a}ltnissen zwischen den Lanthanoid-Ionen auch die genaue Position innerhalb des Netzwerks sowie die Distanz zu anderen Ionen von Interesse. Zur Untersuchung dieser Fragestellungen wird die Umgebungssensitivit{\"a}t der Europium-Lumineszenz ausgenutzt. Die auf diese Weise festgestellte Formiat-Bildung h{\"a}ngt von zahlreichen Parametern ab. Insgesamt stellt sich die im Rahmen dieser Arbeit verwendete Methodik des Einsatzes von Europium als strukturelle Sonde in h{\"o}chstem Maße vielseitig dar und zeigt seine gr{\"o}ßte St{\"a}rke in der Kombination mit weiteren Methoden der Strukturanalytik. Die auf diese Weise genauestens charakterisierten neuartigen Materialien k{\"o}nnen nun gezielt und anwendungsfokussiert weiterentwickelt werden.},
  language  = {de}
}
@misc{SchoenbornHartke2013,
  author    = {Sch{\"o}nborn, Jan Boyke and Hartke, Bernd},
  title     = {Photochemical dynamics of E-methylfurylfulgide},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94516},
  pages     = {2483 -- 2490},
  year      = {2013},
  abstract  = {With the present theoretical study of the photochemical switching of E-methylfurylfulgide we contribute an important step towards the understanding of the photochemical processes in furylfulgide-related molecules. We have carried out large-scale, full-dimensional direct semiempirical configuration-interaction surface-hopping dynamics of the photoinduced ring-closure reaction. Simulated static and dynamical UV/Vis-spectra show good agreement with experimental data of the same molecule. By a careful investigation of our dynamical data, we were able to identify marked differences to the dynamics of the previously studied E-isopropylfurylfulgide. With our simulations we can not only reproduce the experimentally observed quantum yield differences qualitatively but we can also pinpoint two reasons for them: kinematics and pre-orientation. With our analysis, we thus offer straightforward molecular explanations for the high sensitivity of the photodynamics towards seemingly minor changes in molecular constitution. Beyond the realm of furylfulgides, these insights provide additional guidance to the rational design of photochemically switchable molecules.},
  language  = {en}
}