Design of metal-ion dopants and carbonated ions in hydroxyapatite under aqueous solution environment

采用考虑水溶液环境效应的第一性原理方法研究了羟基磷灰石（HAP）中掺杂剂和碳酸根离子的点缺陷能量学。结果表明，由于HAP中的四配位原子结构，Zn^2+取代HAP中的Ca^2+比Mg^2+更有利。与替位Zn^2+相邻的Ca^2+空位也有助于替位Zn^2+的稳定。此外，还发现CO-3 ^2。在高温条件下，在能量上有利地位于OH^-位，这与在高温下形成A型碳酸磷灰石的实验事实很好地一致。

Point defect energetics of dopants and carbonated ions in hydroxyapatite(HAP) was investigated by first-principles analyses involving aqueous solution environment effects. It was found that Zn^2+ substitutes for Ca^2+ in HAP more favorably than Mg^2+ does, due to the four-fold coordinated atomic structure in HAP. Ca^2+ vacancies neighboring substitutional Zn^2+ can also contribute to stabilization of substitutional Zn^2+. Moreover, it was found that CO-3^2. is energetically favorably located at an OH^-site in a high temperature condition, which is in good agreement with an experimental fact of formation of A-type carbonated apatite at a high temperature.