Anomalies in the velocity of longitudinal ultrasonic waves in cesium under the pressure up to 5 GPa |
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Authors: | F F Voronov O V Stalgorova E L Gromnitskaya |
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Institution: | Institute of High Pressure Physics, USSR Academy of Sciences , 142092, Troitsk, Moscow Region, USSR |
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Abstract: | Abstract The velocity of longitudinal ultrasonic waves, ν1,(P), in polycrystalline cesium was measured at 293 ±1K in the pressure interval 0–5 GPa. v 1(P) alterations at BCC-FCC phase transition at 2.3 GPa and at the electronic-structure transformation at 4.3 GPa were obtained. Decrease of v 1(P) to 4.3 GPa after a maximum at ~3.8 GPa were found, that gave evidence to the appearance of a corresponding soft mode in the FCC-Cs phonon spectrum. The peculiarities of dependence v 1(P) correlate with s-conduction electrons promotion to the empty d-band in accordance with the theoretically predicted continuous electronic s-d transformation in Cs. |
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Keywords: | Cesium high pressure phase transition ultrasonic waves velocity soft mode |
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