Abstract

Neutral atoms in liquid helium are known to reside in a bubble-like cavity due to a strong repulsive force between the He and impurity atoms. The interaction of impurity atoms with the bubble produces interesting phenomena such as large broadening and shift of transition lines, non-radiative relaxation, formation of exciplex.[1] Our recent spectroscopic study of molecules, ranging from diatoms to small metal particles, revealed that the properties of molecules in superfluid helium (He II) are far more diverse than those of atoms. This paper reports three topics from our recent results; electronic spectra of large organic molecules, direct infrared absorption spectroscopy, and laser-stimulated motions of small particles in He II.

© 1996 Optical Society of America