@article{nokey,

title = {Kernel Charge Equilibration: Efficient and Accurate Prediction of Molecular Dipole Moments with a Machine-Learning Enhanced Electron Density Model},

author = {C Staacke and S Wengert and C Kunkel and G Cs\'{a}nyi and K Reuter and J T Margraf},

doi = {10.26434/chemrxiv-2021-73w0p},

year  = {2021},

date = {2021-11-25},

journal = {ChemRxiv, Cambridge: Cambridge Open Engage},

abstract = {State-of-the-art machine learning (ML) interatomic potentials use local representations of atomic environments to ensure linear scaling and size-extensivity. This implies a neglect of long-range interactions, most prominently related to electrostatics. To overcome this limitation, we herein present a ML framework for predicting charge distributions and their interactions termed kernel Charge Equilibration (kQEq). This model is based on classical charge equilibration models like QEq, expanded with an environment dependent electronegativity. In contrast to previously reported neural network models with a similar concept, kQEq takes advantage of the linearity of both QEq and Kernel Ridge Regression to obtain a closed-form linear algebra expression for training the models. Furthermore, we avoid the ambiguity of charge partitioning schemes by using dipole moments as reference data. As a first application, we show that kQEq can be used to generate accurate and highly data-efficient models for molecular dipole moments.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optimizing hydrogen binding on Ru sites with RuCo alloy nanosheets for efficient alkaline hydrogen evolution},

author = {C Cai and K Liu and Y Zhu and P Li and Q Wang and B Liu and S Chen and H Li and L Zhu and H Li and J Fu and Y Chen and E Pensa and J Hu and Y-R Lu and T-S Chan and E Cortes and M Liu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202113664},

doi = {https://doi.org/10.1002/anie.202113664},

issn = {1433-7851},

year  = {2021},

date = {2021-11-25},

journal = {Angewandte Chemie International Edition},

volume = {n/a},

number = {n/a},

abstract = {Ruthenium (Ru)-based catalysts, with considerable performance and desirable cost, become highly concerned candidates to replace platinum (Pt) in alkaline hydrogen evolution reaction (HER). The hydrogen binding at Ru sites (Ru-H) is an important factor limiting the HER activity. Herein, density functional theory (DFT) simulations show that the essence of Ru-H binding energy is the strong interaction between the 4dz 2 orbital of Ru and 1s orbital of H. The charge transfer between Ru sites and substrates (Co and Ni) causes the appropriate downward shift of the 4dz 2 -band center of Ru, which results in a Gibbs free energy of 0.022 eV for H* in RuCo system, much decrease compared to 0.133 eV in pure Ru system. This theoretical prediction has been experimentally confirmed using RuCo alloy nanosheets (RuCo ANSs). They were prepared via fast co-precipitation method followed with a mild electrochemical reduction. Structure characterizations reveal that the Ru atoms are embed into Co substrate as isolated active sites with the planar symmetric and Z-direction asymmetric coordination structure, obtaining an optimal 4dz 2 modulated electronic structure. Hydrogen sensor and temperature program desorption (TPD) tests demonstrate the enhanced Ru-H interactions in RuCo ANSs than pure Ru nanoparticles. As a result, the RuCo ANSs reach an ultra-low overpotential of 10 mV at 10 mA/cm 2 and a Tafel slope of 20.6 mV/dec in 1 M KOH, outperforming that of the commercial Pt/C. This holistic work provides a new insight to promote alkaline HER by optimizing metal-H binding energy of active sites.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Achromatic frequency doubling of supercontinuum pulses for transient absorption spectroscopy},

author = {E Keil and P Malevich and J Hauer},

url = {http://www.osapublishing.org/oe/abstract.cfm?URI=oe-29-24-39042},

doi = {10.1364/OE.442400},

year  = {2021},

date = {2021-11-22},

journal = {Optics Express},

volume = {29},

number = {24},

pages = {39042-39054},

abstract = {We present achromatic frequency doubling of supercontinuum pulses from a hollow core fiber as a technique for obtaining tunable ultrashort pulses in the near UV and blue spectral range. Pulse energies are stable on a 1.1% level, averaged over 100 000 shots. By the use of conventional optics only, we compress a 0.2 µJ pulse at a center wavelength of 475 nm to a pulse duration of 12 fs, as measured by X-FROG. We test the capabilities of the approach by employing the ASHG-pulses as a pump in a transient absorption experiment on β-carotene in solution.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}