Rotational dynamics of molecular impurities solvated in 4He clusters. A computational study based on reptation quantum Monte Carlo

The thesis is organized as follows: in the first chapter we provide a short description of the scenario which frames our work. Some significant experiments are presented, together with the questions raised by them, the theoretical investigations they stimulated, and the open issues. The second chapter describes the reptation quantum Monte Carlo method and its theoretical foundations. Technical aspects (the choice of the trial functions, the procedure to calculate the cluster rotational energies) are discussed in third chapter. We also report some studies on the reptation algorithm. In the fourth chapter we apply RQMC for the interpretation of the infrared spectra of CO@HeN [5]. The fifth chapter addresses the problem of the evolution of the rotational dinamics of He solvated rotors toward the nanodroplet regime; two paradigmatic cases, OCS@HeN and HCN@HeN , are studied. Our conclusions are drawn in the last chapter.