The extension of the Periodic System: superheavy — superneutronic

Abstract

Nuclear reactions leading to formation of new Nuclear reactions leading to formation of new superheavy elements and isotopes are discussed. The scope superheavy elements and isotopes are discussed. The scope and limitations of different nuclear reactions (cold and hot and limitations of different nuclear reactions (cold and hot synthesis, fusion of fission fragments, transfer reactions and synthesis, fusion of fission fragments, transfer reactions and reactions with radioactive ion beams) are analyzed, trying reactions with radioactive ion beams) are analyzed, trying to find most promising reactions which may be used at to find most promising reactions which may be used at available facilities. The bibliography includes 70 references available facilities. The bibliography includes 70 references.. I. Historical remarks We begin our discussion of the Periodic Table with some historical remarks about Dmitri Medeleev and Julius Meyer, the discoverers of order and chemical systematics of the elements. The two fathers of the Periodic System, Dmitri Ivanovich Mendeleev (27.1.1834 ± 20.1.1907) and Julius Lothar Meyer (19.3.1830 ± 11.4.1895) were contemporaries close in age. Although coming from different origins, they shared part of their education in science. Meyer was virtually born into a scientific career. He came from a medical family of Oldenburg, Germany, and first pursued a medical degree. In medical school he became interested in chemistry, especially physiological topics like gases in the blood. He earned a medical doctorate at WuÈ rzburg university and subsequently also a physics

Relativistic and quantum electrodynamic effects in superheavy elements

“…In the original paper by Greiner and co-workers, where the dissolution of the 1s 1/2 shell into the negative energy continuum was discussed, the critical charge was estimated to be Z crit = 173 ± 1 for hydrogen-like atoms [178], but later determined to be at Z crit = 164 [179]. We note that Greiner predicts an electronic closed-shell structure for the element with Z = 172 ([Cn]5g6f 7pd8sp9sp 1/2 ), close to this critical charge [180]. Indelicato recently determined Z crit = 173.17 for the 1s 1/2 shell, only slightly influenced by QED effects [175].…”

Relativistic effects on the electronic structure of the heaviest elements. Is the Periodic Table endless?

“…This means that it will dive into the negative energy continuum. This should happen at a critical charge, Z crit , equal to 173±1 depending on the model (see [18,24,27] [28]. Investigations on this subject are still going on requiring considerations beyond standard relativistic mean-field theory.…”

Synthesis of heavy nuclei using damped collisions: A test

“…The fundamental problem was that the nuclei that were produced far above the target nucleus were the result of events with high total kinetic energy loss, i.e., high excitation energies and resulting poor survival probabilities. Very recently, Zagrebaev and Greiner [9][10][11][12][13][14][15][16], using a new model [17] for these collisions, have examined the older experiments and some proposed new experiments ( 232 Th + 250 Cf, 238 U + 238 U, and 238 U + 248 Cm). With their new model, which emphasizes the role of shell effects in damped collisions, they are able to correctly describe the previously measured fragment angular, energy, and charge distributions from the 136 Xe + 209 Bi reaction and the isotopic yields of Cf, Es, Fm, and Md from the 238 U + 248 Cm reaction.…”