Simple diatomic molecules, such as oxygen (O2), have a uniform charge distribution and an interatomic distance of a few ångströms (1 Å = 10−10 m). In a report in Physical Review Letters (85, 2458–2461; 2000), Chris Greene and colleagues predict that a vastly different diatomic molecule, Rb2, could exist in a quantum gas of rubidium atoms — a Bose–Einstein condensate (BEC).
If a rubidium atom with a loosely attached electron forms in a BEC, it could bind with a normal Rb ground state atom, forming an extremely large molecule with an interatomic distance of 500–50,000 Å. The molecule also has a unique charge distribution, shown here, reminiscent of a trilobite fossil. The Rb ion is the green sphere; the other atom is below the twin peaks.
The asymmetry of the charge distribution indicates a large electric dipole. If this unusual molecule can be formed, its dipole will be easily manipulated by small electric fields, unlike normal molecular dipoles, which require much larger (and more expensive) fields.
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Chen, J. The next big thing. Nature 407, 575 (2000). https://doi.org/10.1038/35036670
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DOI: https://doi.org/10.1038/35036670
