Hydrogen Reorganization in Hot Dense Ammonia
Abstract
Hydrogen is known to form stable compounds with a variety of simple molecular solids under high pressure. However, ammonia hydride has not been experimentally observed. Here, through a series of laser-heating diamond anvil cell (LHDAC) experiments, we observed the transparent ionic ammonia transformed into an opaque phase above 150 GPa and 1000 K. Raman spectroscopy reveals a pronounced structural change, accompanied by the emergence of two distinct asymmetric H2 vibrons (ν1 and ν2). A new ionic phase produced following thermally induced dissociation and hydrogen reorganization in hot dense ammonia. The combination of experimental results and first-principles calculations identify this phase as the theoretically predicted ionic P41212 phase of NH7 , which consists of NH4+, H-and H2 units. Our results suggest that the formation of ammonia hydrides follows a thermodynamic pathway distinct from those of other H2-containing mixtures, revealing a new ionic transformation pathway driven by hydrogen reorganization in hot dense ammonia.
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BibTeX
@misc{tao2026hydrogen,
title = {{Hydrogen Reorganization in Hot Dense Ammonia}},
author = {Yu Tao and Jingyi Liu and Li Lei},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.19605},
eprint = {2609.19605},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.19605},
}
RIS
TY - UNPB
TI - Hydrogen Reorganization in Hot Dense Ammonia
AU - Yu Tao
AU - Jingyi Liu
AU - Li Lei
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.19605
UR - https://arxiv.org/abs/2609.19605
AB - Hydrogen is known to form stable compounds with a variety of simple molecular solids under high pressure. However, ammonia hydride has not been experimentally observed. Here, through a series of laser-heating diamond anvil cell (LHDAC) experiments, we observed the transparent ionic ammonia transformed into an opaque phase above 150 GPa and 1000 K. Raman spectroscopy reveals a pronounced structural change, accompanied by the emergence of two distinct asymmetric H_2 vibrons (ν_1 and ν_2). A new ionic phase produced following thermally induced dissociation and hydrogen reorganization in hot dense ammonia. The combination of experimental results and first-principles calculations identify this phase as the theoretically predicted ionic P4_12_12 phase of NH_7 , which consists of NH_4^+, H^-and H_2 units. Our results suggest that the formation of ammonia hydrides follows a thermodynamic pathway distinct from those of other H_2-containing mixtures, revealing a new ionic transformation pathway driven by hydrogen reorganization in hot dense ammonia.
ER -