2009/06/16 by A. A. Râduţâ, Raduta, A. A., R. Budaca +1
Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic and Molecular Physics #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Spectroscopy and Quantum Chemical Studies
paper · pdf · doi:10.48550/arxiv.0906.2911
openalex publication_date 2009/06/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The energy-weighted sum rule for an electric dipole transition operator of a Schiff type differs from the Thomas-Reiche-Kuhn sum rule by several corrective terms which depend on the number of system components, \cal N. The deviations are evaluated by two distinct approaches. One of them is based on the charge density expansion around an uniform distribution and provides an analytical \cal N dependence for the sum rule while, the other one hinges of the RPA approach and yields compact expressions for corrections as function of the RPA amplitudes. Although the formalism might be considered for any many body system, we applied it for illustration, to the case of Na clusters. One concludes that the RPA results for Na clusters obey the modified TRK sum rule.