Kinetics of the high- to low-density amorphous water transition
Kinetics of the high- to low-density amorphous water transition
复制标题
DOI：
10.1088/0953-8984/15/3/301
复制
发表时间：
2003-01-29
影响因子：
2.7
通讯作者：
Fujara, F
中科院分区：
文献类型：
--
作者：
Koza, MM;Schober, H;Fujara, F
原位中子衍射实验研究了高密度非晶态（HDA）水在87 K≤T≤110 K下向低密度非晶态转变的动力学。发现该转变过程包括三个不同的阶段，即高密度基体的退火过程，然后是向低密度态的一级转变，可以在更高的温度T≤或等于 127 K。HDA 状态的退火动力学遵循时间的对数，如在其他显示多晶性的系统中发现的那样。根据成核和生长的转变理论，明显的一级转变遵循阿夫拉米-柯尔莫哥洛夫行为。根据该转变的温度依赖性估计能垒 DeltaE 约为 33 kJ mol(-1)。
In situ neutron diffraction experiments have been carried out to study the kinetics of the transformation of high-density amorphous (HDA) water into its low-density amorphous state at temperatures 87 K less than or equal to T less than or equal to 110 K. It is found that three different stages are comprised in this transformation, namely an annealing process of the high-density matrix followed by a first-order-like transition into a low-density state, which can be further annealed at higher temperatures T less than or equal to 127 K. The annealing kinetics of the HDA state follows the logarithm of time as found in other systems showing polyamorphism. According to the theory of transformation by nucleation and growth the apparent first-order transition follows an Avrami-Kolmogorov behaviour. An energy barrier DeltaE approximate to 33 kJ mol(-1) is estimated from the temperature dependence of this transition.