PhysRevLett_95_215301_2005_haeften_havenith.pdf (635.44 kB)
High Resolution Spectroscopy of NO in Helium Droplets: A Prototype for Open Shell Molecular Interactions in a Quantum Solvent.
journal contribution
posted on 2007-08-02, 10:14 authored by Klaus von Haeften, A. Metzelthin, S. Rudolph, V. Staemmler, M. HavenithWe have measured the high-resolution infrared spectrum of the radical NO in the 2Π1/2 state in superfluid helium nanodroplets. The features are attributed to the Λ doubling splitting and the hyperfine
structure. The hyperfine interaction is found to be unaffected by the He solvation. For the Λ-doubling splitting, we find a considerable increase by 55% compared to the gas phase. This is explained by a confinement of the electronically excited NO states by the surrounding He. The rotational level spacing is decreased to 76% of the gas phase value. The IR transition to the J = 1:5 state is found to be homogeneously broadened. We attribute both observations to the coupling between the molecular rotation
and phonon/roton excitations in superfluid 4He droplets.