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We have expressed the Gibbs free energy for III-V compound semiconductors as a function of pressure and charge transfer through three-body interactions. The lattice energy in it has been represented by a three-body potential consisting of the long-range Coulomb and three-body interactions, and the short-range van der Waals attraction and overlap repulsion, effective up to the second-neighbor ions. We have depicted the phase diagrams and found that the abrupt volume collapses at the phase-transition pressures agree fairly well with the observed data. The phasetransition pressures (17.0, 4.0, 17.1, 18.0, 1.0, and 11. 0 GPa) obtained by us are in close agreement with the experimental data (18.5, 6.7, 22.0, 8.4, 2.2, and 10.8 GPa) for almost all the semiconductors (GaAs, GaSb, GaP, InAs, InSb, and InP) under consideration. The elastic stiffness constants (C») have been found to increase with pressure while the shear moduli (C» -C&z)/2 and C44 decrease with it, and this feature is consistent with the experimental observations.

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Plasma parameters and particularly the external electrical operational parameters are examined with respect to mode transition and hysteresis. The external electrical parameters such as antenna current ͑I c ͒ and antenna voltage ͑V c ͒ amplitudes are measured after the matching network and discussed for an inductively coupled argon discharge. A wide range of discharge conditions by varying applied power ͑up to 150 W at 13.56 MHz͒, gas pressure ͑0.7-7.5 Pa͒, and electrostatic coupling strength are measured for a gaseous electronics conference radio frequency reference cell. The effect on the power coupling efficiency by varying electrostatic coupling strength is studied via implementing two distinct grounded Faraday shields, in addition to the original nonshielded condition. A brief discussion on the evolution of floating potential, plasma potential, electron density, and electron energy distribution function with power and pressure is also presented mainly in context to mode transitions and hysteresis. Relatively smooth transitions in the plasma parameters and in the external electrical parameters are measured close to H to E mode transition region. Contrary to plasma parameters, however, the reverse transition from E to H mode was found to be abrupt in external parameters. The plasma parameters are measured using a commercial Langmuir probe, whereas the antenna currents and voltages are measured using a homebuilt Rogowski coil and capacitor divider, respectively.