A.I. Baz’,
V.I. Gol’danskiia,
Ya.B. Zel’dovichb aSemenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, ul. Kosygina, 4, Moscow, 119991, Russian Federation bAll-Russian Scientific Research Institute of Experimental Physics — Federal Nuclear Centre, prosp. Mira 37, Sarov, Nizhny Novgorod region, 607190, Russian Federation