Phase Transition and Melting Curves of Calcium Fluoride via Molecular Dynamics Simulations  

作　　者：曾召益 陈向荣 朱俊 胡翠娥 

机构地区：[1]Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 [2]College of Physical Science and Technology, Sichuan University, Chengdu 610064 [3]International Centre for Materials Physics, Chinese Academy of Sciences, Shenyang 110016

出　　处：《Chinese Physics Letters》2008年第1期230-233,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant Nos 10576020 and 10776022. The authors would like to thank Professor J. D. Gale for providing us the GULP code.

摘　　要：The phase transition and melting curves of CaF2 are investigated by using the general utility lattice programme （CULP） via the shell model with molecular dynamics method. By calculating the entropy H （at OK） and Cibbs free energy G^＊ （at 30OK）, we find that the phase transition pressure from the face-centred cubic （fee） structure to the orthorhombic structure is 11.40 CPa and 9.33 CPa at OK and 300K, respectively. The modified melting point of the fee CaF2 is in the range of 1650-1733K at OCPa. All these results are well consistent with the available experimental data and other theoretical results. We also obtain that the melting temperature of high pressure phase is 990-1073 K at 10 CPa. Moreover, the temperature dependences of the elastic constants Cij, bulk module B and shear module G are also predicted.The phase transition and melting curves of CaF2 are investigated by using the general utility lattice programme （CULP） via the shell model with molecular dynamics method. By calculating the entropy H （at OK） and Cibbs free energy G^＊ （at 30OK）, we find that the phase transition pressure from the face-centred cubic （fee） structure to the orthorhombic structure is 11.40 CPa and 9.33 CPa at OK and 300K, respectively. The modified melting point of the fee CaF2 is in the range of 1650-1733K at OCPa. All these results are well consistent with the available experimental data and other theoretical results. We also obtain that the melting temperature of high pressure phase is 990-1073 K at 10 CPa. Moreover, the temperature dependences of the elastic constants Cij, bulk module B and shear module G are also predicted.

关 键 词：ELASTIC-CONSTANTS HIGH-PRESSURE CAF2 TEMPERATURE CRYSTAL STABILITY 

分 类 号：O614.231[理学—无机化学]