Castep中几何收敛的标准是:castep文件中,结构优化的提示标语Geometry optimization completed successfully,这说明你的这个结构优化成功。castep中需要测试的两个必设参数是K-points和E-cutoff,通过比较之间的能量值,具体的参考标准,参照一下这篇文献。PHYSICAL REVIEW B 71, 125132 (2005) ,Ab initio investigations of optical properties of the high-pressure phases of ZnO.