Atom by Atom...

Fig. 1 Experimental schematic of the hybrid system and ToF apparatus.

(A) A schematic of the experimental apparatus, including the LQT, the high voltage pulsing scheme (shown as solid and dashed lines), and the ToF. (B) An illustrative experimental time sequence that depicts initialization of a Ba+ crystal, production of BaOCH3+ (visualized as dark ions in the crystal) through reactions with methanol vapor, and subsequent MOT immersion. (C) Sample mass spectra obtained after ejecting the LQT species into the ToF after various MOT immersion times, ti, along with an inset depicting a superimposed fluorescence image of an ion crystal immersed in the Ca MOT. (D) Mass spectra of photofragmentation products collected after inducing photodissociation of BaOCa+. The identified photofragments were used to verify the elemental composition of the product.

Topics: Atomic Physics, Modern Physics, Nanotechnology, Quantum Mechanics

LA physicists have pioneered a method for creating a unique new molecule that could eventually have applications in medicine, food science and other fields. Their research, which also shows how chemical reactions can be studied on a microscopic scale using tools of physics, is reported in the journal Science.

For the past 200 years, scientists have developed rules to describe chemical reactions that they’ve observed, including reactions in food, vitamins, medications and living organisms. One of the most ubiquitous is the “octet rule,” which states that each atom in a molecule that is produced by a chemical reaction will have eight outer orbiting electrons. (Scientists have found exceptions to the rule, but those exceptions are rare.)

But the molecule created by UCLA professor Eric Hudson and colleagues violates that rule. Barium-oxygen-calcium, or BaOCa+, is the first molecule ever observed by scientists that is composed of an oxygen atom bonded to two different metal atoms.

Normally, one metal atom (either barium or calcium) can react with an oxygen atom to produce a stable molecule. However, when the UCLA scientists added a second metal atom to the mix, a new molecule, BaOCa+, which no longer satisfied the octet rule, had been formed. [1]

Abstract

Hypermetallic alkaline earth (M) oxides of formula MOM have been studied under plasma conditions that preclude insight into their formation mechanism. We present here the application of emerging techniques in ultracold physics to the synthesis of a mixed hypermetallic oxide, BaOCa+. These methods, augmented by high-level electronic structure calculations, permit detailed investigation of the bonding and structure, as well as the mechanism of its formation via the barrierless reaction of Ca (3PJ) with BaOCH3+. Further investigations of the reaction kinetics as a function of collision energy over the range 0.005 K to 30 K and of individual Ca fine-structure levels compare favorably with calculations based on long-range capture theory. [2]

1. In step toward ‘controlling chemistry,’ physicists create a new type of molecule, atom by atom, Stuart Wolpert, UCLA Newsroom
2. Synthesis of mixed hypermetallic oxide BaOCa+ from laser-cooled reagents in an atom-ion hybrid trap
Prateek Puri¹, Michael Mills¹, Christian Schneider¹, Ionel Simbotin², John A. Montgomery Jr.², Robin Côté², Arthur G. Suits³, Eric R. Hudson¹,*
1 Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA.
2 Department of Physics, University of Connecticut, Storrs, CT 06269, USA.
3 Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
*Corresponding author. Email: eric.hudson@ucla.edu