A simple method of accounting for correlation effects in electron transitions and its application in finding oscillator strengths and the solar abundance of zirconium

A simple method of accounting for correlation effects in complex atoms and ions, having several open electronic shells, is described. It is based on the use of the so-called transformed radial orbitals to describe the admired electronic configurations in the framework of the superposition-of-configurations method. The method has been applied to calculate the energy spectra and oscillator strengths of electric dipole transitions in neutral and singly ionized zirconium. On the basis of new values of oscillator strengths, the photospheric abundance of zirconium is found to be A(Zr)=log(N-Zr/N-H)+12.00=2.60+/-0.06 and, being in close agreement with the meteoritic abundance, illustrates the reasonable accuracy of the proposed method.