The studies of defects formed by impurity particles (atoms, molecules, exciplexes, clusters,
free electrons, and positive ions) embedded in liquid and solid 4He are reviewed. The …

A little more than a decade ago our team extended the field of defect spectroscopy in
cryocrystals to solid He 4 matrices, in both their body-centered cubic (bcc) and hexagonal …

In order to study fundamental properties of atoms, molecules, clusters, and complexes,
experiments at very low temperatures can be advantageous compared to room temperature …

The longitudinal electronic spin relaxation time of Cs atoms optically polarized in superfluid
helium (He II, 1.5 K) has been measured with special care to cope with a serious decrease …

We have studied both theoretically and experimentally the optical pum** of Cs atoms
trapped in (body-centered-cubic and hexagonal-close-packed) crystalline 4 He matrices …

Searches for violations of the fundamental symmetries of parity P and time reversal T in
atomic and molecular systems provide a powerful tool for precise measurements of the …

In this paper we review research done by the recently founded Fribourg group for Atomic
Physics (FRAP) using laser-assisted spin coherence spectroscopy of atomic samples in …

We propose a direct method of detection of the nuclear anapole moment. It is based on the
existence of a linear Stark shift for alkali atoms in their ground state perturbed by a …

Fullerenes can act as inert cages for highly reactive nitrogen atoms even at room
temperature. Confinement in a cage of less than spherical symmetry as realized in C 70 …

We present a theoretical and experimental study of the laser-induced formation process and
of the emission spectra of Cs* He n exciplexes in the hcp and bcc phases of solid helium …