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Quantitative Rotational to Librational Transition in Dense H₂ and D₂

Peña-Alvarez, Miriam and Afonina, Veronika and Dalladay-Simpson, Philip and Liu, Xiaodi and Howie, Ross T. and Cooke, Peter and Magdău, Ioan B. and Ackland, Graeme J. and Gregoryanz, Eugene (2020) Quantitative Rotational to Librational Transition in Dense H₂ and D₂. Journal of Physical Chemistry Letters, 11 (16). pp. 6626-6631. ISSN 1948-7185.

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Raman spectroscopy demonstrates that the rotational spectrum of solid hydrogen, and its isotope deuterium, undergoes profound transformations upon compression while still remaining in phase I. We show that these changes are associated with a loss of quantum character in the rotational modes and that the angular momentum J gradually ceases to be a good quantum rotational number. Through isotopic comparisons of the rotational Raman contributions, we reveal that hydrogen and deuterium evolve from a quantum rotor to a harmonic oscillator. We find that the mechanics behind this transformation can be well-described by a quantum-mechanical single inhibited rotor, accurately reproducing the striking spectroscopic changes observed in phase I.

Item Type:Article
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Cooke, Peter0000-0002-9977-9194
Additional Information:© 2020 American Chemical Society. Received: June 4, 2020; Accepted: July 10, 2020; Published: July 16, 2020. M.P.-A., G.J.A., and E.G. acknowledge the support of the European Research Council Grant Hecate Reference No. 695527. V.A. gratefully acknowledges SUPA for her Ph.D. research grant. X.-D.L. acknowledges the support of the National Science Foundation of China (Grant No. 11874361). The authors declare no competing financial interest.
Funding AgencyGrant Number
European Research Council (ERC)695527
Scottish Universities Physics AllianceUNSPECIFIED
National Natural Science Foundation of China11874361
Issue or Number:16
Record Number:CaltechAUTHORS:20200717-110919498
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Official Citation:Quantitative Rotational to Librational Transition in Dense H2 and D2. Miriam Peña-Alvarez, Veronika Afonina, Philip Dalladay-Simpson, Xiao-Di Liu, Ross T. Howie, Peter I. C. Cooke, Ioan B. Magdau, Graeme J. Ackland, and Eugene Gregoryanz. The Journal of Physical Chemistry Letters 2020 11 (16), 6626-6631; DOI: 10.1021/acs.jpclett.0c01736
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104430
Deposited By: Tony Diaz
Deposited On:17 Jul 2020 18:20
Last Modified:08 Sep 2020 21:20

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