A simple model for high rotational excitations of molecules in a superfluid

We present a simple quantum mechanical model describing excited rotational states of molecules in superfluid helium nanodroplets, as recently studied non-adiabatic molecular alignment experiments [Cherepanov et al., Phys. Rev. A 104, L061303 (2021)]. show that linear molecule immersed can be seen an effective symmetric top, similar to the structure radicals, such OH or NO, but with angular momentum playing role electronic free molecules. The allows evaluate and centrifugal distortion constants for broad range species explain crossover between light heavy $^4$He terms many-body wavefunction structure. Most important, theory answer question what happens when increases beyond lowest accessible by infrared spectroscopy. Some above mentioned insights acquired analyzing 2x2 matrix.