The homotopy analysis method is used to obtain analytical solutions of the Rayleigh equation for the radial oscillations of a multielectron bubble in liquid helium. The small order approximations for amplitude and frequency fit well with those computed numerically. The results confirm that the homotopy analysis method is a powerful and manageable tool for finding analytical solutions of strongl...

We have studied double photoionization from molecular inner-shell orbitals and investigated the properties of the resultant double core-hole states in molecules, by multielectron coincidence spectroscopy with a magnetic bottle electron spectrometer. A brief summary of our previous studies is presented.

An analytical expression for the effective interaction in a finite multielectron system is derived. The interaction is of finite radius and is density dependent. An analytical expression is also derived for the effective single particle potential and an equation is presented

Multielectron atoms in external fields are essentially more complicated than hydrogen with regard to theoretical treatments. Experimental spectra of helium as well as R-matrix quantum-defect calculations revealed discrepancies between the diamagnetic hydrogen atom and general Rydberg atoms. They appeared most transparent as novel resonance structures in constant scaled-energy recurrence spectra...