| 查看: 1264 | 回复: 2 | ||
| 当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖 | ||
buct2010金虫 (正式写手)
|
[求助]
关于VASP手册中两个参数设置的问题，希望大家指点一下！
|
|
|
（1）LMAXMIX （PAW赝势的设置参数） An additional flag controls up to which l quantum number the onsite PAW charge densities are passed through the charge density mixer and written to the CHGCAR file: LMAXMIX = l The default is LMAXMIX=2. Higher l-quantum numbers are usually not handled by the mixer, i.e. a straight mixing is applied for them (the PAW on-site charge density for higher l quantum numbers is reset precisely to the value corresponding to the present wavefunctions). Usually, it is not required to increase LMAXMIX, but the following two cases are exceptions: • L(S)DA+U calculations require in many cases an increase of LMAXMIX to 4 (or 6 for f-elements) in order to obtain fast convergence to the groundstate. • The CHGCAR file also contains only information up to LMAXMIX for the on-site PAW occupancy matrices. When the CHGCAR file is read and kept fixed in the course of the calculations (ICHARG=11), the results will be necessarily not identical to a selfconsistent run. The deviations can be (or actually are) large for L(S)DA+U calculations. For the calculation of band structures within the L(S)DA+U approach it is strictly required to increase LMAXMIX to 4 (d elements) and 6 (f elements). 问题： 是不是这个参数只对LSDA+U 计算有用？那如果用HF（Hartree-Fock）方法的时候也需要增大它吗（体系有d-f元素）？ （2）LRPA （光学计算中的随机相近似） LRPA = .TRUE. or .FALSE. Default: .FALSE. Usually local field effect are included on the Hartree level only (LRPA=.TRUE.). This means that cell periodic microscopic changes of the local potential related to the change of the Hartree potential are included. If LRPA= .FALSE., however, changes of the Hartree potential and the exchange correlation potential are included. This usually increases the dielectric constants. The final values for the dielectric matrix can be found in the OUTCAR file after the lines. MACROSCOPIC STATIC DIELECTRIC TENSOR (including local field effects in RPA (Hartree)) For LRPA=.FALSE. the dielectric matrix is written after the lines: MACROSCOPIC STATIC DIELECTRIC TENSOR (including local field effects in DFT) The dielectric constants without local field effects is always determined (irregardless of LRPA). The piezoelectric tensors and the Born effective charges as well as the ionic contributions the to dielectric tensor are only calculated for LRPA=.FALSE. 问题： 这个随机相近似对于介电函数有什么影响？是不是可以理解为DFT计算的时候设置LRPA = .TRUE.；HF（Hartree-Fock）计算的时候设置LRPA = .TRUE.？ [ Last edited by buct2010 on 2012-2-29 at 09:23 ] |
回复此楼» 猜你喜欢
论文终于录用啦！满足毕业条件了
已经有12人回复
-
2025年遐想
已经有4人回复
-
投稿Elsevier的杂志（返修），总是在选择OA和subscription界面被踢皮球
已经有8人回复
-
求个博导看看
已经有18人回复
» 本主题相关价值贴推荐，对您同样有帮助:
- 掺杂求高手指点：vasp 不同掺杂浓度模型设置。
已经有8人回复
- vasp 那些参数设置可以影响到磁性计算的磁矩
已经有12人回复
- vasp计算DOS,以及如何判断参数的设置是合理的，达到要求的精度
已经有7人回复
- VASP计算：LORBIT设置出现问题
已经有5人回复
- 表面带电缺陷体系VASP计算参数设置和模型搭建
已经有8人回复
- VASP计算时的几个细节设置问题，希望有经验的人过来指点一下！
已经有23人回复
- 【求助】求助差分电荷密度的脚本！
已经有45人回复
- 【求助】vasp 固定两个坐标 在第三个方向上relax
已经有7人回复
- 【求助】关于VASP中Kpoint设置问题
已经有6人回复
- 【求助完毕】硫酸根离子的结构优化，偶极修正及势能修正。
已经有20人回复
- 【求助】新虫求助！哪位前辈指点一下用vasp做空位缺陷的流程
已经有7人回复
- 【第一性原理活动贴】VASP 官方手册学习活动
已经有56人回复
liliangfang
荣誉版主 (著名写手)
- 1ST强帖: 7
- 应助: 138 (高中生)
- 贵宾: 0.952
- 金币: 10648.7
- 散金: 4575
- 红花: 42
- 沙发: 3
- 帖子: 1856
- 在线: 825.2小时
- 虫号: 1275010
- 注册: 2011-04-23
- 性别: GG
- 专业: 微/纳机械系统
- 管辖: 第一性原理
【答案】应助回帖
感谢参与，应助指数 +1
fzx2008(金币+1): 谢谢分享 2012-02-29 11:41:17
buct2010(金币+5): ★有帮助 谢谢版主，你给的链接是翻译了手册上LRPA，你可能没看清我在每个参数下提的问题。我是想针对这两个参数的设置提一些问题~ 2012-02-29 15:11:09
fzx2008(金币+1): 谢谢分享 2012-02-29 11:41:17
buct2010(金币+5): ★有帮助 谢谢版主，你给的链接是翻译了手册上LRPA，你可能没看清我在每个参数下提的问题。我是想针对这两个参数的设置提一些问题~ 2012-02-29 15:11:09
2楼2012-02-29 11:27:20