Large relativistic effects in molecular properties of the hydride of superheavy element 111

Relativistic and electron correlation contributions in the hydride of the recently discovered superheavy element 111 were studied using ab-initio methods within different relativistic approaches. Relativistic effects decrease the (111)H bond distance by 0.42 إ. As a result of this large bond contraction, the bond distance of (111)H (1.51 إ) is comparable to that of the hydride of its lighter congener AuH (1.52 إ), but below that of AgH (1.60 إ). The dissociation energy is relativistically increased by approximately 1.2 eV and the stretching force constant is more than quadrupled from 1.1 mdyn/إ at the nonrelativistic level to 5.0 mdyn/إ at the relativistic level.