Shape Phase Transitions in the Absorption Spectra of Atomic Clusters

J. M. Pacheco, W.-D. Schöne
1997 Physical Review Letters  
A quantum-mechanical framework for calculating the photoabsorption cross section of atomic clusters, which explicitly includes the thermal motion of the ions, is proposed. We compute the photoabsorption cross section of Na 8 for ionic temperatures below and above melting. At equilibrium, the line shape of Na 8 is dominated by two peaks separated by 200 meV. This structure is found to survive up to T 100 K. With increasing temperatures, the cross section undergoes a shape phase transition such
more » ... e transition such that, at T 300 K, the double-peak structure has changed into a broad and asymmetric line shape dominated by a single peak, providing an excellent fit to the available experimental data. [S0031-9007 (97) 04846-1] PACS numbers: 36.40.Gk, 36.40.Ei
doi:10.1103/physrevlett.79.4986 fatcat:b4rs2biadzfetbktoqpb455m24