Pressure Raman spectra of LiK_0.8(NH₄)_0.2SO₄

Abstract

Raman spectra of LiK 0.8 (NH 4 ) 0.2 SO 4 were obtained as a function of applied pressure. The measurements were carried out using a microscope to focus the light into a spot size of 2 µm, in order to avoid probing a multi-domain sample. With increasing pressure, many of the Raman peaks are shifted towards higher wavenumbers. At certain pressures the number of peaks changes and theñ vs P plots are discontinuous. These effects occurring at P = 0.9 and 2.5 GPa were interpreted as structural phase transitions. The pressure coefficients are given for modes derived from the pure E 2 and A(LO) symmetries of a-phase.

Structural properties in mixed LiK1−(NH4) SO4 (x= 0, 0.06, and 1) crystals by nuclear magnetic resonance

“…Recently, gamma-irradiated LiK 0.97 (NH 4 ) 0.03 SO 4 single crystals were studied by using electron paramagnetic resonance (EPR), and the principal values of the g and hyperfine tensors were reported by Kartal et al [18]. Brillouin spectroscopy was also used to study the phase transitions of LiK 0.8 (NH 4 ) 0.2 SO 4 mixed crystals [19][20][21].…”