Quasiparticle energies of small alkali-metal clusters $({\mathrm{Li}}_n,$ ${\mathrm{Na}}_n,$ ${\mathrm{K}}_n;$ $n=2,4,6,8)$ are evaluated from first principles by means of the $\mathrm{GW}$ approximation with the generalized plasmon-pole model. An all-electron mixed-basis approach, in which wave function is represented as a linear combination of both plane waves and atomic orbitals, is adopted in the calculation. Obtained quasiparticle energies (ionization potential and electron affinity) are in good agreement with available experimental data.

• Received 27 December 2001

DOI:https://doi.org/10.1103/PhysRevB.65.245109