The dimer of trans-N-methylacetamide serves as a simple model for hydrogen bonds in peptides, free of any backbone distortions. Its preferred structures represent benchmark systems for an accurate quantum chemical description of protein interactions. The trimer allows for either two linear or three strained hydrogen bonds, with the former being the only structural motif considered so far in the literature, but the latter winning in energy by a large margin due to London dispersion. A combination of linear Raman and infrared supersonic jet techniques with B3LYP-D3/aug-cc-pVTZ quantum chemical predictions corrects earlier tentative spectroscopic assignments based on a hybrid density functional without dispersion correction. Linear Amide I-III infrared spectra of the jet-cooled monomer are compared to those recently obtained by action spectroscopy.

By a combination of linear FTIR and Raman jet spectroscopy, racemic trans-1,2-cyclohexanediol is shown to form an energetically unrivalled S 4 -symmetric heterochiral dimer in close analogy to 1,2-ethanediol.Analogous experiments with enantiopure trans-1,2-cyclohexanediol reveal the spectral signature of at least three unsymmetric homochiral dimers. A comparison to signal-enhanced spectra of 1,2-ethanediol and to calculations uncovers at least three transiently homochiral dimer contributions as well. In few of these dimer structures, the intramolecular OHÁ Á ÁO contact present in monomeric 1,2-diols survives, despite the kinetic control in supersonic jet expansions. This provides further insights into the dimerisation mechanism of conformationally semi-flexible molecules in supersonic jets. Racemisation upon dimerisation is shown to be largely quenched under jet cooling conditions, whereas it should be strongly energy-driven at higher temperatures. The pronounced energetic preference for heterochiral aggregation of vicinal diols is also discussed in the context of chirality-induced spin selectivity. † Electronic supplementary information (ESI) available: Interactive and static structures, tables of experimental and computational details, energy diagrams for different levels of calculation, and additional experimental spectra. See

The theoretical description of spectral signatures for weakly bound hydrogen contacts between alcohol groups is challenging and remains poorly characterised. By combining Raman jet spectroscopy with appropriately scaled harmonic DFT...

In the discussion of chirality recognition, steric considerations and strongly directed interactions such as hydrogen bonds are primarily discussed. However, given the sheer size of biomolecules, it is expected that...

We report the resulls of variational estimates of the binding energy of excitons in quantum wells along the eEect of the image potential.

The authors report the results of a variational calculation of the binding energy of shallow donors in quantum wells along with the effects of the image potential.

Additionally, I would like to thank the institutes workshops for always helping out with any issues that came up. Here, I would like to especially thank Reinhard Hildebrandt and Mike Zippert of the mechanical workshop. The former helped to design a custom heat-exchanger and the latter helped with the acquisition of new pressure regulators. Furthermore, I would also like to thank Rainer Oswald for helping out when problems arose with the Chemie-Cluster and making quantum-chemistry programs available as modules. Thanks also go to Stefan Grimme who allowed for the use of the xTB and CREST programs on the Chemie-Cluster which have been developed by his group. Special thanks also goes to Laura N. Schiebel, for whom I had the pleasure to supervise her bachelor thesis. She also continued researching open questions of her bachelor project as a research assistant (Junior Bencher), funded by the DFG as part of the RTG. I would also like to thank her for proof-reading large parts of this work.Furthermore, I would like to thank the entire Suhm group for the great atmosphere, be it during conferences, table football games, group trips or game nights. I am also grateful I to Robert Medel for proof-reading the monomer chapter and providing computational data for tri-tert-butyl-methanol. Further thanks go to Maxim Gawrilow, Arman Nejad, Sophie Schweer and Taija Fischer for help and advise regarding experimental and nonexperimental work. Additionally, I would like to thank the entire Schnell Group for the warm welcome during my research stay in Hamburg.Last but not least, I would like to thank my family and friends for their support.

The role‐exchanging concerted torsional motion of two hydrogen atoms in the homochiral dimer of trans‐1,2‐cyclohexanediol was characterized through a combination of broadband rotational spectroscopy and theoretical modeling. The results reveal that the concerted tunneling motion of the hydrogen atoms leads to the inversion of the sign of the dipole moment components along the a and b principal axes, due to the interchange motion that cooperatively breaks and reforms one intermolecular hydrogen bond. This motion is also coupled with two acceptor switching motions. The energy difference between the two ground vibrational states arising from this tunneling motion was determined to be 29.003(2) MHz. The corresponding wavefunctions suggest that the two hydrogen atoms are evenly delocalized on two equivalent potential wells, which differs from the heterochiral case where the hydrogen atoms are confined in separate wells, as the permutation‐inversion symmetry breaks down. This intriguing contrast in hydrogen‐atom behavior between homochiral and heterochiral environments could further illuminate our understanding of the role of chirality in intermolecular interactions and dynamics.