Hydrogen modes in KH2PO4 under pressure from ab initio calculations and inelastic neutron scattering

Hydrogen modes in KH2PO4 under pressure from ab initio calculations and inelastic neutron scattering Full article

Journal

Physical Review B
ISSN: 2469-9969

Output data

Year: 2025, Volume: 112, Number: 21, Article number : 214101, Pages count : 11 DOI: 10.1103/r9gl-4j51

Authors

Abalmasov V.A. ¹ , Ivanov A.S. ² , Sadykov R.A. ³ , Belushkin A.V. ^4,5

Affiliations

1	Sobolev Institute of Mathematics, 630090 Novosibirsk, Russia
2	Institut Max von Laue–Paul Langevin, 38042 Grenoble, France
3	Institute for Nuclear Research RAS, 117312 Moscow, Russia
4	International Intergovernmental Organization Joint Institute for Nuclear Research, Frank Laboratory of Neutron Physics, 141980 Dubna, Russia
5	Institute of Physics, Kazan Federal University, 420008 Kazan, Russia

Funding (1)

Sobolev Institute of Mathematics

FWNF-2022-0021

The nature of the phonon triplet in the region of OH-stretching modes in hydrogen-bonded materials is often explained by the interplay of OH-stretching modes and combinations and overtones of OH-bending modes. To elucidate both contributions in KH2PO4 (KDP), we compare the pressure dependence of the OH-bending and stretching modes from ab initio calculations and inelastic neutron scattering (INS) measurements. The ab initio calculations predict a hardening of OH-bending modes and a softening of OH-stretching modes with pressure. At the same time, INS measurements in the region of OH-stretching modes indicate a hardening of the phonon triplet together with the bending modes. This means that this triplet in INS measurements is mainly due to combinations and overtones of OH-bending modes, while the intensity of OH-stretching modes appears to be relatively low. This conclusion may also apply to other hydrogen-bonded materials.

Abalmasov V.A. , Ivanov A.S. , Sadykov R.A. , Belushkin A.V.
Hydrogen modes in KH2PO4 under pressure from ab initio calculations and inelastic neutron scattering
Physical Review B. 2025. V.112. N21. 214101 :1-11. DOI: 10.1103/r9gl-4j51

Submitted:	Jul 28, 2025
Accepted:	Oct 9, 2025
Published online:	Dec 1, 2025

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