Quantitative Rotational to Librational Transition in Dense H₂ and D₂
Abstract
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.
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.Attached Files
Supplemental Material - jz0c01736_si_001.pdf
Files
Name | Size | Download all |
---|---|---|
md5:b30abae158053b3f18916f06c0a68e8c
|
17.3 MB | Preview Download |
Additional details
- Eprint ID
- 104430
- Resolver ID
- CaltechAUTHORS:20200717-110919498
- 695527
- European Research Council (ERC)
- Scottish Universities Physics Alliance
- 11874361
- National Natural Science Foundation of China
- Created
-
2020-07-17Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field