High-pressure elastic properties of the orientationally disordered and hydrogen-bonded phase of solid HCl

Abstract

By using in situ Brillouin spectroscopy in a diamond-anvil cell, we have measured the direction-dependent acoustic velocities and the refractive index in the orientationally disordered and hydrogen-bonded solid phase I of hydrogen chloride ͑HCl͒ at pressures up to 4.5 GPa and 300 K, leading to the first determinations of adiabatic elastic constants (C 11 , C 12 , and C 44 ), bulk modulus (B S ), and the elastic anisotropy ͑A͒ to 4.5 GPa. These results are compared with those of solids of the same type H 2 S and NH 3 . We investigate the effect of the strength of hydrogen bonds on the A value which is sensitive to the rotation-translation coupling of molecular motions under compression. ͓S0163-1829͑99͒01318-1͔

Hydrogen bond symmetrization and superconducting phase of HBr and HCl under high pressure: An ab initio study

“…24 At room temperature, [11][12][13][25][26][27] the disordered phase I transforms to the ordered phase III at 13 GPa for HBr and 19 GPa for HCl. At 100 K, a phase transition likely associated with hydrogen bond symmetrization was observed in HBr at about 32 GPa, while there was no further evidence of a phase transition at least to 42 GPa for HCl.…”

Raman study of phase transition and hydrogen bond symmetrization in solid DCl at high pressure

“…The phase diagram involving I, II, III and plausible IЈ phases was determined by Raman and Brillouin scattering measurements in a temperature range of 20-300 K and a pressure range of 0.1 MPa-20 GPa. [10][11][12][13] At room temperature, the disordered phase I transformed to the ordered phase III at 19.0 GPa in HCl and at 13.0 GPa in HBr. A further transition into a high pressure phase ͑phase IV͒ with symmetrized hydrogen bonds was observed at 51 and 39 GPa for HCl and HBr, respectively, at ambient temperature by Raman measurement up to several 10 GPa.…”

High-pressure Brillouin scattering in a simple molecular system

“…The acoustic velocity (v) for the probed acoustic phonon is critically dependent on the crystal orientation, even for a cubic crystalline system. In figure 1, the direction dependences of the acoustic velocities for LA and two transverse (TA 1 , slow; TA 2 , fast) modes are shown for three kinds of elastic anisotropy (A = 1, 2.5, and 3.4), where A is defined as the square of the ratio of the acoustic velocities of TA 2 to TA 1 propagating along the 110 direction for a cubic crystalline system having three elastic constants C 11 , C 12 , and C 44 [15]:…”

“…Shimizu and his group [7] developed in situ high-pressure Brillouin spectroscopy which enables us to determine simultaneously acoustic velocities and the orientation of a crystal grown in the DAC. This method reveals elastic properties of pressure-induced single-crystalline H 2 S [7,8], CO 2 [9], H 2 O [10][11][12], CH 4 [13], NH 3 [14], HCl [15], HBr [16], Kr [17], and Ar [2] at room temperature. The Zha and Carnegie group [18] combined high-pressure Brillouin study and x-ray diffraction measurements at each applied pressure, and succeeded in determining six elastic constants of solid H 2 up to P = 24 GPa at room temperature.…”