The Radial and Rotational Coupling Terms between the Quasi-Molecular States of He2++

Abstract

The radial and rotational coupling matrix elements between the 1 Σ g + (2sσ 2 ,2pσ 2 ,2pπ 2 ), \(^{1}\varPi_{\text{g}}(2\text{p}\sigma 2\text{p}\pi)\) and 1 Δ g (2pπ 2 ) quasi-molecular states of He 2 ++ have been calculated using an elaborate CI wave function in the range of internuclear separation from 0.0 to 0.5 atomic units. It is pointed out that, because of the configuration mixing, the rotational coupling matrix elements which are zero at the united atom limit or in the single configuration approximation have finite values at small R . The radial coupling matrix element between the 1 Σ g + (2sσ 2 ) and 1 Σ g + (2pσ 2 ) states is about 10 atomic units at the pseudo-crossing near R =0.2. The accuracy of the calculation of the radial coupling matrix elements is discussed.