Rotational excitations in K1-x(NH4)xI mixed crystals: A neutron scattering study

C. Bostoen; G. Coddens; W. Wegener

doi:10.1063/1.457401

Rotational excitations in K_1-x(NH₄)_xI mixed crystals: A neutron scattering study

C. Bostoen, G. Coddens, W. Wegener

Research output › peer-review

Abstract

A neutron scattering study was performed on K_1-x (NH ₄)_XI mixed crystals (x≤0.44) at temperatures T≤20 K. Our results show in a direct fashion that the NH₄ ⁺-NH₄⁺ interaction contributes significantly to the crystal-field potential. A quantitative discussion in terms of a locally perturbed field is applied to the x = 0.02 results. The barrier increase due to the presence of a single NH₄⁺ ion cannot be ascribed to octopole-octopole interactions alone. A qualitative model, which includes dipole-dipole interactions, is presented. The temperature study on a sample with x = 0.28 shows a continuous transition from a quantum regime to a classical regime of reorientational motions.

Original language	English
Pages (from-to)	6337-6344
Number of pages	8
Journal	The Journal of Chemical Physics
Volume	91
Issue number	10
DOIs	https://doi.org/10.1063/1.457401
State	Published - 1989

ASJC Scopus subject areas

General Physics and Astronomy
Physical and Theoretical Chemistry

Access to Document

10.1063/1.457401

Cite this

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title = "Rotational excitations in K1-x(NH4)xI mixed crystals: A neutron scattering study",

abstract = "A neutron scattering study was performed on K1-x (NH 4)XI mixed crystals (x≤0.44) at temperatures T≤20 K. Our results show in a direct fashion that the NH4 +-NH4+ interaction contributes significantly to the crystal-field potential. A quantitative discussion in terms of a locally perturbed field is applied to the x = 0.02 results. The barrier increase due to the presence of a single NH4+ ion cannot be ascribed to octopole-octopole interactions alone. A qualitative model, which includes dipole-dipole interactions, is presented. The temperature study on a sample with x = 0.28 shows a continuous transition from a quantum regime to a classical regime of reorientational motions.",

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language = "English",

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T1 - Rotational excitations in K1-x(NH4)xI mixed crystals

T2 - A neutron scattering study

AU - Bostoen, C.

AU - Coddens, G.

AU - Wegener, W.

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AB - A neutron scattering study was performed on K1-x (NH 4)XI mixed crystals (x≤0.44) at temperatures T≤20 K. Our results show in a direct fashion that the NH4 +-NH4+ interaction contributes significantly to the crystal-field potential. A quantitative discussion in terms of a locally perturbed field is applied to the x = 0.02 results. The barrier increase due to the presence of a single NH4+ ion cannot be ascribed to octopole-octopole interactions alone. A qualitative model, which includes dipole-dipole interactions, is presented. The temperature study on a sample with x = 0.28 shows a continuous transition from a quantum regime to a classical regime of reorientational motions.

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