@article{SuessWehnerDostaletal.2019, author = {S{\"u}ß, Jasmin and Wehner, Johannes G. and Dost{\´a}l, Jakub and Engel, Volker and Brixner, Tobias}, title = {Mapping of exciton-exciton annihilation in a molecular dimer via fifth-order femtosecond two-dimensional spectroscopy}, series = {Journal of Physical Chemistry Letters}, volume = {150}, journal = {Journal of Physical Chemistry Letters}, number = {10}, doi = {10.1063/1.5086151}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178420}, pages = {104304}, year = {2019}, abstract = {We present a theoretical study on exciton-exciton annihilation (EEA) in a molecular dimer. This process is monitored using a fifth-order coherent two-dimensional (2D) spectroscopy as was recently proposed by Dost{\´a}l et al. [Nat. Commun. 9, 2466 (2018)]. Using an electronic three-level system for each monomer, we analyze the different paths which contribute to the 2D spectrum. The spectrum is determined by two entangled relaxation processes, namely, the EEA and the direct relaxation of higher lying excited states. It is shown that the change of the spectrum as a function of a pulse delay can be linked directly to the presence of the EEA process.}, subject = {Exziton}, language = {en} } @unpublished{SuessWehnerDostaletal.2019, author = {S{\"u}ß, Jasmin and Wehner, Johannes G. and Dost{\´a}l, Jakub and Engel, Volker and Brixner, Tobias}, title = {Mapping of exciton-exciton annihilation in a molecular dimer via fifth-order femtosecond two-dimensional spectroscopy}, series = {Journal of Physical Chemistry Letters}, journal = {Journal of Physical Chemistry Letters}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178482}, year = {2019}, abstract = {We present a theoretical study on exciton-exciton annihilation (EEA) in a molecular dimer. This process is monitored using a fifth-order coherent two-dimensional (2D) spectroscopy as was recently proposed by Dost{\´a}l et al. [Nat. Commun. 9, 2466 (2018)]. Using an electronic three-level system for each monomer, we analyze the different paths which contribute to the 2D spectrum. The spectrum is determined by two entangled relaxation processes, namely, the EEA and the direct relaxation of higher lying excited states. It is shown that the change of the spectrum as a function of a pulse delay can be linked directly to the presence of the EEA process.}, subject = {Exziton}, language = {en} } @article{BrueningWehnerHausneretal.2016, author = {Br{\"u}ning, Christoph and Wehner, Johannes and Hausner, Julian and Wenzel, Michael and Engel, Volker}, title = {Exciton dynamics in perturbed vibronic molecular aggregates}, series = {Structural Dynamics}, volume = {3}, journal = {Structural Dynamics}, doi = {10.1063/1.4936127}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126085}, pages = {043201}, year = {2016}, abstract = {A site specific perturbation of a photo-excited molecular aggregate can lead to a localization of excitonic energy. We investigate this localization dynamics for laser-prepared excited states. Changing the parameters of the electric field significantly influences the exciton localization which offers the possibility for a selective control of this process. This is demonstrated for aggregates possessing a single vibrational degree of freedom per monomer unit. It is shown that the effects identified for the molecular dimer can be generalized to larger aggregates with a high density of vibronic states.}, language = {en} } @article{EngelAlbertSchubert2013, author = {Engel, Volker and Albert, Julian and Schubert, Alexander}, title = {Two-dimensional vibronic spectroscopy of molecular predissociation}, series = {New Journal of Physics}, journal = {New Journal of Physics}, doi = {10.1088/1367-2630/15/2/025008}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96199}, year = {2013}, abstract = {We calculate two-dimensional (2D) spectra reflecting the time-dependent electronic predissociation of a diatomic molecule. The laser-excited electronic state is coupled non-adiabatically to a fragment channel, leading to the decay of the prepared quasi-bound states. This decay can be monitored by the three-pulse configuration employed in optical 2D spectroscopy. It is shown that in this way it is possible to state-selectively characterize the time-dependent population of resonance states with different lifetimes. A model of the NaI molecule serves as a numerical example.}, language = {en} } @article{GuthHueserRothetal.2021, author = {Guth, Sabine and H{\"u}ser, Stephanie and Roth, Angelika and Degen, Gisela and Diel, Patrick and Edlund, Karolina and Eisenbrand, Gerhard and Engel, Karl-Heinz and Epe, Bernd and Grune, Tilman and Heinz, Volker and Henle, Thomas and Humpf, Hans-Ulrich and J{\"a}ger, Henry and Joost, Hans-Georg and Kulling, Sabine E. and Lampen, Alfonso and Mally, Angela and Marchan, Rosemarie and Marko, Doris and M{\"u}hle, Eva and Nitsche, Michael A. and R{\"o}hrdanz, Elke and Stadler, Richard and van Thriel, Christoph and Vieths, Stefan and Vogel, Rudi F. and Wascher, Edmund and Watzl, Carsten and N{\"o}thlings, Ute and Hengstler, Jan G.}, title = {Contribution to the ongoing discussion on fluoride toxicity}, series = {Archives of Toxicology}, volume = {95}, journal = {Archives of Toxicology}, number = {7}, issn = {0340-5761}, doi = {10.1007/s00204-021-03072-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-307161}, pages = {2571-2587}, year = {2021}, abstract = {Since the addition of fluoride to drinking water in the 1940s, there have been frequent and sometimes heated discussions regarding its benefits and risks. In a recently published review, we addressed the question if current exposure levels in Europe represent a risk to human health. This review was discussed in an editorial asking why we did not calculate benchmark doses (BMD) of fluoride neurotoxicity for humans. Here, we address the question, why it is problematic to calculate BMDs based on the currently available data. Briefly, the conclusions of the available studies are not homogeneous, reporting negative as well as positive results; moreover, the positive studies lack control of confounding factors such as the influence of well-known neurotoxicants. We also discuss the limitations of several further epidemiological studies that did not meet the inclusion criteria of our review. Finally, it is important to not only focus on epidemiological studies. Rather, risk analysis should consider all available data, including epidemiological, animal, as well as in vitro studies. Despite remaining uncertainties, the totality of evidence does not support the notion that fluoride should be considered a human developmental neurotoxicant at current exposure levels in European countries.}, language = {en} } @article{SchuergerEngel2023, author = {Sch{\"u}rger, Peter and Engel, Volker}, title = {Differential Shannon entropies characterizing electron-nuclear dynamics and correlation: momentum-space versus coordinate-space wave packet motion}, series = {Entropy}, volume = {25}, journal = {Entropy}, number = {7}, issn = {1099-4300}, doi = {10.3390/e25070970}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-362670}, year = {2023}, abstract = {We calculate differential Shannon entropies derived from time-dependent coordinate-space and momentum-space probability densities. This is performed for a prototype system of a coupled electron-nuclear motion. Two situations are considered, where one is a Born-Oppenheimer adiabatic dynamics, and the other is a diabatic motion involving strong non-adiabatic transitions. The information about coordinate- and momentum-space dynamics derived from the total and single-particle entropies is discussed and interpreted with the help of analytical models. From the entropies, we derive mutual information, which is a measure for the electron-nuclear correlation. In the adiabatic case, it is found that such correlations are manifested differently in coordinate- and momentum space. For the diabatic dynamics, we show that it is possible to decompose the entropies into state-specific contributions.}, language = {en} } @article{SchuergerEngel2023, author = {Sch{\"u}rger, Peter and Engel, Volker}, title = {On the relation between nodal structures in quantum wave functions and particle correlation}, series = {AIP Advances}, volume = {13}, journal = {AIP Advances}, number = {12}, doi = {10.1063/5.0180004}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350361}, year = {2023}, abstract = {We study the influence of nodal structures in two-dimensional quantum mechanical densities on wave packet entanglement. This is motivated by our recent study [Entropy, 25, 970 (2023)], which showed that the mutual information derived from the momentum-space probability density of a coupled two-particle system exhibits an unusual time dependence, which is not encountered if the position-space density is employed in the calculation. In studying a model density, here, we identify cases where the mutual information increases with the number of nodes in the wave function and approaches a finite value, whereas in this limit, the linear correlation vanishes. The results of the analytical model are then applied to interpret the correlation measures for coupled electron-nuclear dynamics, which are treated by numerically solving the time-dependent Schr{\"o}dinger equation.}, language = {en} } @article{SchmidtFantuzziKlopfetal.2021, author = {Schmidt, Paul and Fantuzzi, Felipe and Klopf, Jonas and Schr{\"o}der, Niklas B. and Dewhurst, Rian D. and Braunschweig, Holger and Engel, Volker and Engels, Bernd}, title = {Twisting versus delocalization in CAAC- and NHC-stabilized boron-based biradicals: the roles of sterics and electronics}, series = {Chemistry - A European Journal}, volume = {27}, journal = {Chemistry - A European Journal}, number = {16}, doi = {10.1002/chem.202004619}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256636}, pages = {5160-5170}, year = {2021}, abstract = {Twisted boron-based biradicals featuring unsaturated C\(_2\)R\(_2\) (R=Et, Me) bridges and stabilization by cyclic (alkyl)(amino)carbenes (CAACs) were recently prepared. These species show remarkable geometrical and electronic differences with respect to their unbridged counterparts. Herein, a thorough computational investigation on the origin of their distinct electrostructural properties is performed. It is shown that steric effects are mostly responsible for the preference for twisted over planar structures. The ground-state multiplicity of the twisted structure is modulated by the σ framework of the bridge, and different R groups lead to distinct multiplicities. In line with the experimental data, a planar structure driven by delocalization effects is observed as global minimum for R=H. The synthetic elusiveness of C\(_2\)R\(_2\)-bridged systems featuring N-heterocyclic carbenes (NHCs) was also investigated. These results could contribute to the engineering of novel main group biradicals.}, language = {en} } @article{FerreiraGamazonAlEjehetal.2019, author = {Ferreira, Manuel A. and Gamazon, Eric R. and Al-Ejeh, Fares and Aittom{\"a}ki, Kristiina and Andrulis, Irene L. and Anton-Culver, Hoda and Arason, Adalgeir and Arndt, Volker and Aronson, Kristan J. and Arun, Banu K. and Asseryanis, Ella and Azzollini, Jacopo and Balma{\~n}a, Judith and Barnes, Daniel R. and Barrowdale, Daniel and Beckmann, Matthias W. and Behrens, Sabine and Benitez, Javier and Bermisheva, Marina and Bialkowska, Katarzyna and Blomqvist, Carl and Bogdanova, Natalia V. and Bojesen, Stig E. and Bolla, Manjeet K. and Borg, Ake and Brauch, Hiltrud and Brenner, Hermann and Broeks, Annegien and Burwinkel, Barbara and Cald{\´e}s, Trinidad and Caligo, Maria A. and Campa, Daniele and Campbell, Ian and Canzian, Federico and Carter, Jonathan and Carter, Brian D. and Castelao, Jose E. and Chang-Claude, Jenny and Chanock, Stephen J. and Christiansen, Hans and Chung, Wendy K. and Claes, Kathleen B. M. and Clarke, Christine L. and Couch, Fergus J. and Cox, Angela and Cross, Simon S. and Czene, Kamila and Daly, Mary B. and de la Hoya, Miguel and Dennis, Joe and Devilee, Peter and Diez, Orland and D{\"o}rk, Thilo and Dunning, Alison M. and Dwek, Miriam and Eccles, Diana M. and Ejlertsen, Bent and Ellberg, Carolina and Engel, Christoph and Eriksson, Mikael and Fasching, Peter A. and Fletcher, Olivia and Flyger, Henrik and Friedman, Eitan and Frost, Debra and Gabrielson, Marike and Gago-Dominguez, Manuela and Ganz, Patricia A. and Gapstur, Susan M. and Garber, Judy and Garc{\´i}a-Closas, Montserrat and Garc{\´i}a-S{\´a}enz, Jos{\´e} A. and Gaudet, Mia M. and Giles, Graham G. and Glendon, Gord and Godwin, Andrew K. and Goldberg, Mark S. and Goldgar, David E. and Gonz{\´a}lez-Neira, Anna and Greene, Mark H. and Gronwald, Jacek and Guen{\´e}l, Pascal and Haimann, Christopher A. and Hall, Per and Hamann, Ute and He, Wei and Heyworth, Jane and Hogervorst, Frans B. L. and Hollestelle, Antoinette and Hoover, Robert N. and Hopper, John L. and Hulick, Peter J. and Humphreys, Keith and Imyanitov, Evgeny N. and Isaacs, Claudine and Jakimovska, Milena and Jakubowska, Anna and James, Paul A. and Janavicius, Ramunas and Jankowitz, Rachel C. and John, Esther M. and Johnson, Nichola and Joseph, Vijai and Karlan, Beth Y. and Khusnutdinova, Elza and Kiiski, Johanna I. and Ko, Yon-Dschun and Jones, Michael E. and Konstantopoulou, Irene and Kristensen, Vessela N. and Laitman, Yael and Lambrechts, Diether and Lazaro, Conxi and Leslie, Goska and Lester, Jenny and Lesueur, Fabienne and Lindstr{\"o}m, Sara and Long, Jirong and Loud, Jennifer T. and Lubiński, Jan and Makalic, Enes and Mannermaa, Arto and Manoochehri, Mehdi and Margolin, Sara and Maurer, Tabea and Mavroudis, Dimitrios and McGuffog, Lesley and Meindl, Alfons and Menon, Usha and Michailidou, Kyriaki and Miller, Austin and Montagna, Marco and Moreno, Fernando and Moserle, Lidia and Mulligan, Anna Marie and Nathanson, Katherine L. and Neuhausen, Susan L. and Nevanlinna, Heli and Nevelsteen, Ines and Nielsen, Finn C. and Nikitina-Zake, Liene and Nussbaum, Robert L. and Offit, Kenneth and Olah, Edith and Olopade, Olufunmilayo I. and Olsson, H{\aa}kan and Osorio, Ana and Papp, Janos and Park-Simon, Tjoung-Won and Parsons, Michael T. and Pedersen, Inge Sokilde and Peixoto, Ana and Peterlongo, Paolo and Pharaoh, Paul D. P. and Plaseska-Karanfilska, Dijana and Poppe, Bruce and Presneau, Nadege and Radice, Paolo and Rantala, Johanna and Rennert, Gad and Risch, Harvey A. and Saloustros, Emmanouil and Sanden, Kristin and Sawyer, Elinor J. and Schmidt, Marjanka K. and Schmutzler, Rita K. and Sharma, Priyanka and Shu, Xiao-Ou and Simard, Jaques and Singer, Christian F. and Soucy, Penny and Southey, Melissa C. and Spinelli, John J. and Spurdle, Amanda B. and Stone, Jennifer and Swerdlow, Anthony J. and Tapper, William J. and Taylor, Jack A. and Teixeira, Manuel R. and Terry, Mary Beth and Teul{\´e}, Alex and Thomassen, Mads and Th{\"o}ne, Kathrin and Thull, Darcy L. and Tischkowitz, Marc and Toland, Amanda E. and Torres, Diana and Truong, Th{\´e}r{\`e}se and Tung, Nadine and Vachon, Celine M. and van Asperen, Christi J. and van den Ouweland, Ans M. W. and van Rensburg, Elizabeth J. and Vega, Ana and Viel, Alexandra and Wang, Qin and Wappenschmidt, Barbara and Weitzel, Jeffrey N. and Wendt, Camilla and Winqvist, Robert and Yang, Xiaohong R. and Yannoukakos, Drakoulis and Ziogas, Argyrios and Kraft, Peter and Antoniou, Antonis C. and Zheng, Wei and Easton, Douglas F. and Milne, Roger L. and Beesley, Jonathan and Chenevix-Trench, Georgia}, title = {Genome-wide association and transcriptome studies identify target genes and risk loci for breast cancer}, series = {Nature Communications}, volume = {10}, journal = {Nature Communications}, organization = {EMBRACE Collaborators, GC-HBOC Study Collaborators, GEMO Study Collaborators, ABCTB Investigators, HEBON Investigators, BCFR Investigators}, doi = {10.1038/s41467-018-08053-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228024}, year = {2019}, abstract = {Genome-wide association studies (GWAS) have identified more than 170 breast cancer susceptibility loci. Here we hypothesize that some risk-associated variants might act in non-breast tissues, specifically adipose tissue and immune cells from blood and spleen. Using expression quantitative trait loci (eQTL) reported in these tissues, we identify 26 previously unreported, likely target genes of overall breast cancer risk variants, and 17 for estrogen receptor (ER)-negative breast cancer, several with a known immune function. We determine the directional effect of gene expression on disease risk measured based on single and multiple eQTL. In addition, using a gene-based test of association that considers eQTL from multiple tissues, we identify seven (and four) regions with variants associated with overall (and ER-negative) breast cancer risk, which were not reported in previous GWAS. Further investigation of the function of the implicated genes in breast and immune cells may provide insights into the etiology of breast cancer.}, language = {en} } @article{SaalfrankFantuzziKupferetal.2020, author = {Saalfrank, Christian and Fantuzzi, Felipe and Kupfer, Thomas and Ritschel, Benedikt and Hammond, Kai and Krummenacher, Ivo and Bertermann, R{\"u}diger and Wirthensohn, Raphael and Finze, Maik and Schmid, Paul and Engel, Volker and Engels, Bernd and Braunschweig, Holger}, title = {cAAC-Stabilized 9,10-diboraanthracenes—Acenes with Open-Shell Singlet Biradical Ground States}, series = {Angewandte Chemie International Edition}, volume = {59}, journal = {Angewandte Chemie International Edition}, number = {43}, doi = {10.1002/anie.202008206}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217795}, pages = {19338 -- 19343}, year = {2020}, abstract = {Narrow HOMO-LUMO gaps and high charge-carrier mobilities make larger acenes potentially high-efficient materials for organic electronic applications. The performance of such molecules was shown to significantly increase with increasing number of fused benzene rings. Bulk quantities, however, can only be obtained reliably for acenes up to heptacene. Theoretically, (oligo)acenes and (poly)acenes are predicted to have open-shell singlet biradical and polyradical ground states, respectively, for which experimental evidence is still scarce. We have now been able to dramatically lower the HOMO-LUMO gap of acenes without the necessity of unfavorable elongation of their conjugated π system, by incorporating two boron atoms into the anthracene skeleton. Stabilizing the boron centers with cyclic (alkyl)(amino)carbenes gives neutral 9,10-diboraanthracenes, which are shown to feature disjointed, open-shell singlet biradical ground states.}, language = {en} } @article{KleinBarthelsJoheetal.2020, author = {Klein, Philipp and Barthels, Fabian and Johe, Patrick and Wagner, Annika and Tenzer, Stefan and Distler, Ute and Le, Thien Anh and Schmid, Paul and Engel, Volker and Engels, Bernd and Hellmich, Ute A. and Opatz, Till and Schirmeister, Tanja}, title = {Naphthoquinones as covalent reversible inhibitors of cysteine proteases — studies on inhibition mechanism and kinetics}, series = {Molecules}, volume = {25}, journal = {Molecules}, number = {9}, issn = {1420-3049}, doi = {10.3390/molecules25092064}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203791}, year = {2020}, abstract = {The facile synthesis and detailed investigation of a class of highly potent protease inhibitors based on 1,4-naphthoquinones with a dipeptidic recognition motif (HN-l-Phe-l-Leu-OR) in the 2-position and an electron-withdrawing group (EWG) in the 3-position is presented. One of the compound representatives, namely the acid with EWG = CN and with R = H proved to be a highly potent rhodesain inhibitor with nanomolar affinity. The respective benzyl ester (R = Bn) was found to be hydrolyzed by the target enzyme itself yielding the free acid. Detailed kinetic and mass spectrometry studies revealed a reversible covalent binding mode. Theoretical calculations with different density functionals (DFT) as well as wavefunction-based approaches were performed to elucidate the mode of action.}, language = {en} } @article{SaalfrankFantuzziKupferetal.2020, author = {Saalfrank, Christian and Fantuzzi, Felipe and Kupfer, Thomas and Ritschel, Benedikt and Hammond, Kai and Krummenacher, Ivo and Bertermann, R{\"u}diger and Wirthensohn, Raphael and Finze, Maik and Schmid, Paul and Engel, Volker and Engels, Bernd and Braunschweig, Holger}, title = {cAAC-stabilisierte 9,10-Diboraanthracene - offenschalige Singulettbiradikale}, series = {Angewandte Chemie}, volume = {132}, journal = {Angewandte Chemie}, number = {43}, doi = {10.1002/ange.202008206}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218582}, pages = {19502 -- 19507}, year = {2020}, abstract = {Geringe HOMO-LUMO-Abst{\"a}nde und eine hohe Ladungstr{\"a}germobilit{\"a}t pr{\"a}destinieren die h{\"o}heren Acene f{\"u}r Anwendungen im Bereich der Organoelektronik. Die Leistungsf{\"a}higkeit derartiger Verbindungen steigt hierbei dramatisch mit der Anzahl anellierter Benzolringe. Gr{\"o}ßere Acenmengen sind synthetisch bisher jedoch nur f{\"u}r Acene bis Heptacen verl{\"a}sslich zug{\"a}nglich. Theoretischen Studien zufolge besitzen (Oligo)acene offenschalige Singulettbiradikal- und (Poly)acene polyradikalische Grundzust{\"a}nde. Eindeutige experimentelle Belege f{\"u}r diese Vorhersagen sind hingegen {\"a}ußerst selten. Durch den Einbau von zwei Boratomen in das Anthracengrundger{\"u}st konnten wir den HOMO-LUMO-Abstand von Acenen dramatisch verringern und zwar ohne die Notwendigkeit einer Ausweitung des konjugierten π-Systems. Stabilisierung der Borzentren durch cyclische (Alkyl)(amino)carbene lieferte hierbei neutrale 9,10-Diboraanthracene mit disjunkten, offenschaligen Singulettbiradikal-Grundzust{\"a}nden.}, language = {en} }