The influence of nuclear spin and isotopic isomers of H2, HD, and D2 weakly bound complexes

• Applicant: Professor Dr. Daniel A. Obenchain
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 523979060

To better understand the subtle binding interactions of ortho and para hydrogen in weakly bound complexes, we will use rotational spectroscopy to analyze the hyperfine splitting of simple aromatic rings when forming complexes with molecular hydrogen. We will use the deuterated isotopes of hydrogen and a series of furans and halogenated benzenes to reduce the complexity of the target compared to our previous studies in this field. Previous studies have left the dipolar nuclear spin/nuclear spin coupling tensor only partially determined. As such, we have only been able to estimate the intermolecular parameters of H2-bound complexes, but not the subtle intra-molecular properties of hydrogen that are expected to change upon forming a complex. The study aims at providing better experimental results to compare to computational predictions. This is essential as most computational methods only partially consider the changes in binding distances and energy when predicting the differences in ortho-bound hydrogen vs. para-bound hydrogen. The work will use a series of rotational spectrometers, both chirp-pulse broadband, and cavity FTMW spectrometers.

• DFG Programme: Research Grants