| This thesis focuses on investigation of guest-host interaction between the unique environment inside the helium droplets and the embedded foreign species. Fast vibronic relaxation of nitrogen dioxide (NO2) molecule in helium droplets had been previously explained in terms of coupling to the nearest non-superfluid shell of helium atoms. Experiments described in this work aim to further characterize this shell by co-embedding nitrogen dioxide with rare gas (RG) atoms, Ne, Ar, Kr, and Xe. The excitation energy range was extended to lower energies (17300 -- 17700 cm-1), where the spectrum is less congested. The effects of adding RG atoms on a strong, isolated NO2 line were examined. Additional spectral feature, attributed to NO2-Ne complex, was observed. The mechanisms responsible for this feature, as well as for the absence of any effects upon addition of other rare gases, are discussed. |
