Impact of octupole vibrations on the fine structure of the ISGMR in ²⁰⁸ Pb

The effects of the phonon-phonon coupling on the fine structure of the Isoscalar Giant Monopole Resonance (ISGMR) are studied in the quasiparticle-phonon model based on the Skyrme Energy Density Functional (EDF). Characteristic energy scales are extracted from the fine structure using continuous wavelet transforms. It is shown that an extension of the two-phonon space allowing for octupole phonons substantially enriches the spectrum of the energy scales. As an example, the ISGMR for the doubly magic 208 Pb is discussed.