Dresden 2026 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 91: Superconductivity: Theory II
TT 91.4: Vortrag
Donnerstag, 12. März 2026, 18:15–18:30, HSZ/0101
Unraveling Quantum Effects of Flexible Molecules in Superfluid Solvents — •Katharina Leitmann1, Harald Forbert1,2, and Dominik Marx1 — 1Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, GER — 2Center for Solvation Science ZEMOS, Ruhr-Universität Bochum, 44780 Bochum, GER
Protonated methane (CH5+) is a fluxional molecule whose sensitivity to its environment makes it an excellent probe for low-temperature molecular interactions. We investigate CH5+ microsolvation in para-hydrogen clusters (pH2)n at low temperatures using two distinct simulation approaches: Ring Polymer Molecular Dynamics at 15 K to compute IR spectra and a hybrid simulation approach that combines Path Integral Molecular Dynamics for CH5+ and bosonic Path Integral Monte Carlo to establish Bose-Einstein statistics of the (pH2)n quantum solvation environment, subject to bosonic exchange at 1 K.
All simulations are based on highly accurate High-dimensional Neural Network Potentials and the IR spectra are computed using a Neural Network Dipole Moment Surface, both parameterized using CCSD(T) theory. Our simulations demonstrate stable solvation of CH5+ at least up to n=12 pH2 molecules, which build the first solvation shell. We revealed that the structure of CH5+ is not significantly perturbed by the solvation with pH2. However, we found significant fluctuations in the large amplitude motion of CH5+ associated with partial hydrogen scrambling as a function of cluster size n. These dynamic influences are consistently observed in the IR spectra, underscoring the robustness of our findings across different methodologies and temperatures.
Keywords: path integral simulations; neural network potentials; para-hydrogen; ring polymer molecular dynamics; spectroscopy