Synchrotron x-ray diffraction reveals a pressure induced crystallization at about 3.4 GPa and apolymorphic transition near 10.3 GPa when compressed a liquid GaIn eutectic alloy up to ~13 GPa atroom temperature in a diamond anvil cell. Upon decompression, the high pressure crystalline phaseremains almost unchanged until it transforms to the liquid state at around 2.3 GPa. The ab initiomolecular dynamics calculations can reproduce the low pressure crystallization and give some hints onthe understanding of the transition between the liquid and the crystalline phase on the atomic level.The calculated pair correlation function g(r) shows a non-uniform contraction reflected by the differentcompressibility between the short (1st shell) and the intermediate (2nd to 4th shells). It is concludedthat the pressure-induced liquid-crystalline phase transformation likely arises from the changes in localatomic packing of the nearest neighbors as well as electronic structures at the transition pressure
