Résumé
The study of small/medium size molecules inside nanoscale cavities of diverse host material, e.g.,clathrates hydrates, cryogenic fluids (or superfluids), fullerenes, carbon nanotubes and zeolites, has receiveda great deal of attention over the past years due to their broad application domain (condensed matter physics,nanomaterial sciences, geoscience, quantum chemistry, astrophysical and planetary sciences, biophysics, ...).However the description of such systems is often far from complete. Indeed,in such nanoscale confinement, the translational center-of-mass motionsof the caged molecules are quantized and strongly coupled to themolecular rotations, which are quantized too. To interpret experimentaldata, theoretical tools are useful but we need to go beyond the simple harmonicapproximation as the guest molecule presents very large amplitudemotions (translation and rotation) and its interaction with the nanoscalecavity can be far from harmonic. A rigorous quantum treatment of the intricatecoupled translation-rotation (TR) dynamics of the caged diatomicmolecules is far from a routine task.