Rick Steven W
Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, USA.
J Chem Phys. 2005 Mar 1;122(9):094504. doi: 10.1063/1.1853351.
Computer simulations of ice Ih with different proton orientations are presented. Simulations of proton disordered ice are carried out using a Monte Carlo method which samples over proton degree of freedom, allowing for the calculation of the dielectric constant and for the examination of the degree of proton disorder. Simulations are also presented for two proton ordered structures of ice Ih, the ferroelectric Cmc2(1) structure or ice XI and the antiferroelectric Pna2(1) structure. These simulations indicate that a transition to a proton ordered phase occurs at low temperatures (below 80 K). The symmetry of the ordered phase is found to be dependent on the water potential. The stability of the two proton ordered structures is due to a balance of short-ranged interactions which tend to stabilize the Pna2(1) structure and longer-range interactions which stabilize the Cmc2(1) structure.
本文展示了具有不同质子取向的冰Ih的计算机模拟。利用蒙特卡罗方法对质子无序冰进行模拟，该方法对质子自由度进行采样，从而能够计算介电常数并研究质子无序程度。同时还展示了冰Ih的两种质子有序结构的模拟结果，即铁电Cmc2(1)结构或冰XI以及反铁电Pna2(1)结构。这些模拟表明，在低温（低于80K）下会发生向质子有序相的转变。发现有序相的对称性取决于水势。两种质子有序结构的稳定性源于短程相互作用和长程相互作用之间的平衡，短程相互作用倾向于稳定Pna2(1)结构，长程相互作用则稳定Cmc2(1)结构。
