The search for element 102

Abstract

SYNTHESIS AND IDENTIFICATION of chemical elements with atomic numbers greater than 100 (fermium) have been accomplished with extremely small amounts, literally on a one-atom-at-a-time basis. At the present time these elements can only be formed with accelerated ions, ranging from neon to helium, that bombard targets from uranium to einsteinium. Because of their minuscule transmutation cross sections, such experiments are extremely difficult to perform, and often the results are subject to error and uncertainty of interpretation.

Elements Beyond 100, Present Status and Future Prospects

“…The indications that 258Fm likely has a very short half-life for decay by spontaneous fission, perhaps shorter than 5 sec, were described in Section 2.6.7. Such a short half-life is in disagreement with semiempirical considerations such as those of Viola, Wilkins & Seaborg (46,48) , although strictly empirical extrapolations such as those of Ghiorso (21) and Foreman & Seaborg (29) are consistent with such a short half-life. A half-life of a few seconds or less for 258Fm might indicate an energy-level gap at N = 156-158 similar to that at N = 152-154.…”

“…: 104 than do the earlier calculations of Dorn (30) or the purely empirical extrapolations (21, 29) of existing data. As an example we have Ghiorso's (21) results, presented in Figure 11, which lead to the prediction of half-lives in the important region just beyond the actinide ele ments some 104 times shorter than those predicted through the semiempirical method of Viola, Wilkins & Seaborg (46,48) . If the half-lives are indeed so short, this would have an important impact on the prospects for producing and identifying new elements just beyond the actinide region ; this question is discussed in Section 3.3.…”

“…Preliminary attempts to produce element 114 have been made at Berke ley (243,244) and Dubna (245) . At Berkeley the target nuclei 244Cm and 2 4 8Cm were bombarded with the available 4°Ar ions, which might produce relatively unfavorable nuclei (i.e., with N -Z less than 60) such as 280114 or 284114 (as illustrated in the reactions written above) .…”

“…II summarizes the �urrent nuclear data and compares the results published by the Berkeley(20,21) and Dubna(12) groups. 2.2.2 Chemical properties.-Recent tracer work by the Berkeley group has established the chemical prop erties of element 102 quite well.…”

Nobelium non-believers

“…They soon realized some of their earlier half-life and isotope identifications had been wrong and the revised analysis of the data aligned more closely with the Dubna findings. In their rebuttal, the Berkeley group emphasized their 'right according to tradition' to name the element, but conceded that they would be content with nobelium 3 . This was ignored in the Soviet Union, where the local discovery of element 102 was lauded officially.…”