Browsing by Author "Jerabek P"

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    Oganesson: A Noble Gas Element That Is Neither Noble Nor a Gas
    (Wiley-VCH GmbH, 2020-12-21) Smits OR; Mewes J-M; Jerabek P; Schwerdtfeger P
    Oganesson (Og) is the last entry into the Periodic Table completing the seventh period of elements and group 18 of the noble gases. Only five atoms of Og have been successfully produced in nuclear collision experiments, with an estimate half-life for ²⁹⁴⁄₁₁₈ Og of 0. 69⁺⁰‘⁶⁴⁄⁻₀¸₂₂ ms.⁽¹⁾ With such a short lifetime, chemical and physical properties inevitably have to come from accurate relativistic quantum theory. Here, we employ two complementary computational approaches, namely parallel tempering Monte-Carlo (PTMC) simulations and first-principles thermodynamic integration (TI), both calibrated against a highly accurate coupled-cluster reference to pin-down the melting and boiling points of this super-heavy element. In excellent agreement, these approaches show Og to be a solid at ambient conditions with a melting point of ≈325 K. In contrast, calculations in the nonrelativistic limit reveal a melting point for Og of 220 K, suggesting a gaseous state as expected for a typical noble gas element. Accordingly, relativistic effects shift the solid-to-liquid phase transition by about 100 K.
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    Tipping the Balance Between the bcc and fcc Phase Within the Alkali and Coinage Metal Groups.
    (Wiley-VCH GmbH on behalf of Angewandte Chemie International Edition, 2023-10-25) Robles-Navarro A; Jerabek P; Schwerdtfeger P
    Why the Group 1 elements crystallize in the body-centered cubic (bcc) structure, and the iso-electronic Group 11 elements in the face-centered cubic (fcc) structure, remains a mystery. Here we show that a delicate interplay between many-body effects, vibrational contributions and dispersion interactions obtained from relativistic density functional theory offers an answer to this long-standing controversy. It also sheds light on the Periodic Table of Crystal Structures. A smooth diffusionless transition through cuboidal lattices gives a detailed insight into the bcc→fcc phase transition for the Groups 1 and 11 elements.