Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
Phys Rev Lett. 2010 Jul 2;105(1):017802. doi: 10.1103/PhysRevLett.105.017802. Epub 2010 Jun 30.
The x-ray absorption spectra of water and ice are calculated with a many-body approach for electron-hole excitations. The experimental features, including the effects of temperature change in the liquid, are reproduced from configurations generated by ab initio molecular dynamics. The spectral difference between the solid and the liquid is due to two major short-range order effects. One, due to breaking of hydrogen bonds, enhances the pre-edge intensity in the liquid. The other, due to a nonbonded molecular fraction in the first coordination shell, affects the main spectral edge in the conversion of ice to water. This effect may not involve hydrogen bond breaking as shown by experiment in high-density amorphous ice.
本文采用多体方法计算了水和冰的 X 射线吸收谱。实验特征，包括液体中温度变化的影响，都是由从头算分子动力学生成的构型来再现的。固体和液体之间的光谱差异是由于两个主要的短程有序效应造成的。一是由于氢键的断裂，增强了液体中预边的强度。另一个是由于第一个配体壳中非键合的分子部分，影响了冰向水转化时的主要谱边。正如高密无定形冰实验所表明的那样，这种效应可能不涉及氢键的断裂。
