IR spectroscopy of pyridine–water structures in helium nanodroplets

Abstract

We present the results of an IR spectroscopic study of pyridine-water heterodimer formation in helium nanodroplets. The experiments were carried out in the frequency range of the pyridine C-H stretch region (3055-3100 cm À1 ) and upon water deuteration in the D-O stretch region (2740-2800 cm À1 ). In order to come to an unambiguous assignment we have determined the angle between the permanent dipole and the vibrational transition moment of the aggregates. The experiments have been accompanied by theoretical simulations which yielded two minimum structures with a 16.28 kJ mol À1 energy difference.The experimentally observed bands were assigned to two structures with different H-bonds: an NÁ Á ÁH bond and a bifurcated OÁ Á ÁH-C bond.

Setting up the HyDRA blind challenge for the microhydration of organic molecules

“…However, for such a soft and flexible hydrogen bond, it is likely that the cold transition obtainable in a jet expansion occurs at significantly lower wavenumber. While ultracold helium droplets should exhibit much smaller, but still significant 17,83 environmental shifts than a room temperature gas phase measurement, a corresponding recent study 67 does not address the relevant spectral range and isotope composition.…”

Setting up the HyDRA blind challenge for the microhydration of organic molecules

“…However, for such a soft and flexible hydrogen bond, it is likely that the cold transition obtainable in a jet expansion occurs at significantly lower wavenumber. While ultracold helium droplets should exhibit much smaller, but still significant 17,82 environmental shifts than a room temperature gas phase measurement, a corresponding recent study 66 does not address the relevant spectral range and isotope composition.…”

High-resolution two-dimensional electronic spectroscopy reveals homogeneous line profiles in isolated nanoparticles

“…In this method, isolated, cryogenically cooled nanoclusters are doped with single particles, forming a clean, enclosed nanosystem in the gas phase. By changing the cluster material or co-doping with solvent molecules, the effects of the environment on single particles can be studied [14,15,16,17]. Common cluster species are superfluid helium (He) nanodroplets, on the one hand, and heavier rare-gases forming solid clusters, on the other hand.…”