Frozen-planet resonances in doubly excited helium atom; adiabatic approach Tasko P. Grozdanov, Alexander A. Gusev, Evgeni A. Solov’ev and Sergue I. Vinitsky Eur. Phys. J. D, 74 7 (2020) 161 Published online: 23 July 2020 DOI: 10.1140/epjd/e2020-10202-9