RUI: Spectroscopy in bulk superfluid 4He

This research concentrates on the study of atomic and molecular impurities in superfluid 4He. Such impurities form either snowball or bubble states in the liquid where the former corresponds to a pileup of liquid around the impurity with well defined surrounding solvent shells and the latter to a void created by the repulsive Pauli exchange interaction with ground state helium atoms. As superfluid helium remains liquid down to 0 K, it offers a unique environment for studying 1) solvation effects and their role in chemical reactions, 2) the superfluid response at atomic scales, 3) the formation of exotic chemical species and 4) the time-dependent impurity - superfluid response by using spectroscopic tools.