Lee Sung Keun, Eng Peter J, Mao Ho-kwang, Meng Yue, Shu Jinfu
School of Earth and Environmental Sciences, Seoul National University, Seoul, 151-742 Korea.
Phys Rev Lett. 2007 Mar 9;98(10):105502. doi: 10.1103/PhysRevLett.98.105502. Epub 2007 Mar 6.
We report the first in situ boron K-edge inelastic x-ray scattering (IXS) spectra for alkali borate glasses (Li2B4O7) at high pressure up to 30 GPa where pressure-induced coordination transformation from three-coordinated to four-coordinated boron was directly probed. Coordination transformation (reversible upon decompression) begins around 5 GPa and the fraction of four-coordinated boron increases with pressure from about 50% (at 1 atm) to more than 95% (at 30 GPa) with multiple densification mechanisms, evidenced by three distinct pressure ranges for (d[4]B/dP)T. The lithium K-edge IXS spectrum for Li-borate glasses at 5 GPa shows IXS features similar to that at 1 atm, suggesting that the Li environment does not change much with pressure up to 5 GPa. These results provide improved understanding of the structure of low-z glass at high pressure.
我们报道了碱金属硼酸盐玻璃（Li2B4O7）在高达30 GPa的高压下的首个原位硼K边非弹性X射线散射（IXS）光谱，其中直接探测了压力诱导的硼从三配位到四配位的配位转变。配位转变（减压时可逆）在约5 GPa开始，四配位硼的比例随压力从约50%（在1个大气压下）增加到超过95%（在30 GPa下），存在多种致密化机制，这由(d[4]B/dP)T的三个不同压力范围证明。5 GPa下锂硼酸盐玻璃的锂K边IXS光谱显示出与1个大气压下相似的IXS特征，表明在高达5 GPa的压力下锂环境变化不大。这些结果有助于更好地理解高压下低Z玻璃的结构。
