UMD Physicists Discover Crystal Symmetry Controls Nuclear Spin States of Molecular Hydrogen



by Clarence Oxford

Los Angeles, CA (SPX) Could 01, 2026

Chemical physicists on the College of Maryland have demonstrated that the nuclear spin states of molecular hydrogen could be managed just by freezing it inside dry-ice crystals – no magnetic fields or chemical catalysts required. The findings, printed in Bodily Evaluate Letters on April 29, 2026, open potential paths towards improved hydrogen gasoline storage, extra secure quantum reminiscence, and sharper astronomical measurements of comet formation temperatures.



Molecular hydrogen exists in two nuclear spin configurations: para-H2, wherein the spins of the 2 hydrogen atoms cancel, and ortho-H2, wherein they add collectively. Ortho-H2 has three substates outlined by the rotational route of the nucleus. As hydrogen cools, ortho-H2 naturally tends to transform to the lower-energy para-H2 state. The UMD staff discovered that when H2 is frozen inside dry-ice crystals, the crystalline symmetry of the encompassing stable blocks that conversion for 2 of the three ortho-H2 substates whereas leaving one accessible.



“The massive discovering is that, relying on what ice we put an H2 molecule into, its quantum dynamics are totally depending on the encompassing setting,” mentioned Nathan McLane, a chemical physics graduate pupil and the paper’s lead creator.



The mechanism is rooted within the geometry of crystalline carbon dioxide. Its molecular construction imposes a set of symmetry-based choice guidelines that govern which quantum transitions are permitted. Senior creator Leah Dodson, an assistant professor in UMD’s Division of Chemistry and Biochemistry, framed the broader significance: “We present experimentally that when molecular hydrogen – the only molecule – is confined inside totally different molecular crystals, the symmetry of the encompassing stable determines which quantum spin states can interconvert and which stay protected.”



The staff additionally confirmed these guidelines could be intentionally relaxed. Introducing nitrogen dioxide into the dry-ice crystal lattice alters its crystalline properties, enabling all three ortho-H2 substates to transform to para-H2. That potential to tune the permitted transitions represents the core experimental advance.



The U.S. Division of Power, which funded the analysis, has a direct curiosity in a single near-term utility: hydrogen gasoline storage. As a result of totally different nuclear spin states of hydrogen require totally different quantities of vitality to warmth up, enriching particular spin states whereas defending others might make storage techniques extra environment friendly and secure. When ortho-H2 converts to para-H2 it releases warmth, an element that gasoline managers should account for rigorously. The staff plans to increase the method to methane as a subsequent step.



A second utility entails astrochemistry. NASA at present estimates the formation temperatures of comets by measuring the proportions of ortho and para water the comets launch – a calculation that rests on assumptions about how nuclear spins evolve in cometary environments that haven’t been experimentally verified. Dodson, who additionally works in astrochemistry, mentioned the brand new laboratory method could possibly be used to check these assumptions straight.



The quantum computing angle is extra speculative however conceptually notable. Defending quantum states from decoherence is a central engineering problem for qubit techniques, and the power to isolate particular spin substates utilizing solely crystal geometry means that supplies design alone, moderately than complicated electromagnetic equipment, might in precept supply a path to state safety. McLane acknowledged the present setup shouldn’t be a sensible qubit platform – “it is simply H2 in dry ice” – however Dodson described the work as foundational. “This work is setting out the foundational guidelines for a way quantum states would possibly turn out to be protected,” she mentioned.



UMD chemistry main LeAnh Duckett co-authored the paper with McLane and Dodson. The analysis was supported by the U.S. Division of Power Workplace of Science Early Profession Analysis Program underneath Award Quantity DE-SC0024262.



Analysis Report: Setting-Imposed Choice Guidelines for Nuclear-Spin Conversion of H2 in Molecular Crystals


Associated Hyperlinks

College of Maryland Faculty of Pc, Mathematical and Pure Sciences

Understanding Time and Area



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