2021

Heßberger, F. P.; Block, M.; Düllmann, Ch. E.; Yakushev, A.; Leino, M.; Uusitalo, J.

In two recent papers by Pore et al. and Khuyagbaatar et al., discovery of the new isotope Md244 was reported. The decay data, however, are conflicting. While Pore et al. report two isomeric states decaying by α emission with Eα(1)=8.66(2) MeV, T1/2(1)=0.4-0.1+0.4 s and Eα(2)=8.31(2) MeV, T1/2(2)≈6 s, Khuyagbaatar et al. [Phys. Rev. Lett. 125, 142504 (2020).PRLTAO0031-900710.1103/PhysRevLett.125.142504] report only a single transition with a broad energy distribution of Eα=(8.73-8.86) MeV and T1/2=0.30-0.09+0.19 s. The data published in Pore et al. are very similar to those published for Md245m [Eα=8.64(2), 8.68(2) MeV, T1/2=0.35-0.16+0.23 s [V. Ninov, F. P. Heßberger, S. Hofmann, H. Folger, G. Münzenberg, P. Armbruster, A. V. Yeremin, A. G. Popeko, M. Leino, and S. Saro, Z. Phys. A 356, 11 (1996).ZPAHEX0939-792210.1007/s002180050141]]. Therefore, we compare the data presented for Md244 in Pore et al. with those reported for Md245 in Ninov et al. and also in Khuyagbaatar et al. We conclude that the data presented in Pore et al. shall be attributed to Md245 with small contributions (one event each) from Fm245 and probably Md246.