Theoretical approach to the structure, energy and electronic spectroscopy of O@(4He)N doped nanodroplets

Abstract

A DFT approach has been used to investigate helium nanodroplets, (⁴He)_N, doped with a single oxygen atom (ground (³P) and first excited (¹D, ¹S) electronic states). To do this, the O(¹D, ¹S)–He diatomic interaction potentials have been determined at the icMRCI ab initio level, as they were not available from the experiments. The structure of the O@(⁴He)_N nanodroplets (N up to 3000) and the electronic emission spectrum of the O(¹D ← ¹S) transition in ⁴He_N were the main properties examined. The results have been interpreted on the basis of the strength of the O–He interaction, as a function of the electronic state of the impurity, and the point symmetry of the helium atoms' geometrical configurations. These results can be useful in studies of chemical processes taking place in helium nanodroplets involving or leading to the production of O atoms.