Electronic structure and optical absorption spectra of Y2 and Zr2 dimers

The electron structure, ionization potentials from valent levels and energies of optic transitions of Y2 and Zr2 dimers are calculated within the framework of discrete-variatin Xα-method. It is shown that the symmetry state 1Σg+ is the main state of Y2 and Zr2 dimers, and the atoms in dimers have high-spin 4dn+15s1 configuration. The chemical binding in Y2 has the dominating 5s-5s nature which is revealed in a considerable interatomic distance; binding of 4d-electrons brings about a significant decrease in the bond length in Zr2 dimer. The theoretical spectrum of optical absorption of Zr2 agrees well with the obtained experimental spectrum of this molecule isolated in the organ matrix