Effect of surface fluctuations in the line shape of plasma resonances in small metal clusters

The line shape of plasma resonances in small sodium clusters (8≤N≤20) is calculated taking into account quadrupole fluctuations of the cluster shape. At room temperatures, an average value of Γ/${\omega }_M$∼0.1 for the damping factor is found. In the case of deformed clusters, these fluctuations are not able to wash out the multipeaked structure associated with the dipole resonance along the principal axes of the cluster.