| 查看: 4179 | 回复: 19 | ||
| 【奖励】 本帖被评价10次，作者xirainbow增加金币 6.25 个 | ||
| 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 | ||
[资源]
【原创】ecutwfc and ecutrho
|
||
|
以下内容来自我的博客： blog.sina.com.cn/nkasir When I use PWgui to edit input file of pw.x, a warning always jumps out:"some variable are not set: List of unset variables: ecutrho". In my mind, in general plane wave code, only the energy cutoff for wavefunctions is adequate. Therefore, I never set ecutrho manually. This is the instruction of ecutrho:" Type: REAL Default: 4 * ecutwfc Description: kinetic energy cutoff (Ry) for charge density and potential May be larger ( for ultrasoft PP ) or somewhat smaller ( but not much smaller ) than the default value. Note that if you have norm-conserving PP only, setting it to a larger value than the default is a waste of time." But now, I know that it is only true for norm-conserving pseudopotentials, not for utral-soft ones. I find the following statement at: http://encina.northwestern.edu/i ... nd_PWSCF_in_general "We are going to use ultrasoft pseudopotentials here. In the case of norm-conserving pseudopotentials from Lab 2, ecutrho (the charge density cutoff) is automatically determined by 4*ecutwfc. However, in the case of ultrasoft pseudopotentials, we need an augmented charge around the ion core, so ecutrho should be higher than 4*ecutwfc. The usual value is 25-35 Ry for ecutwfc and 200-300 Ry for ecutrho. You might want to do a convergence check. Keep in mind that the value you should look at is the energy difference or force, not the absolute value of the energy (the energy will not converge unless you use very, very high ecutwfc and ecutrho). " [ Last edited by xirainbow on 2009-7-16 at 11:31 ] |
回复此楼» 猜你喜欢
欢迎发来filecode的Mz6后的代码验证其规律
已经有118人回复
-
今天放榜吗？
已经有15人回复
-
售SCI一区T0P文章，我:8.O55.1.O.54,科目全,可十急
已经有3人回复
-
售SCI文章，我:8O.5.5.1O.54,科目全,可十急
已经有4人回复
-
售SCI一区T0P文章，我:8.O55.1.O.54,科目全,可十急
已经有5人回复
-
售SCI一区T0P文章，我:8.O.55.1.O.54,科目齐全,可+急
已经有5人回复
-
filecode，4个jtjc了
已经有11人回复
-
filecode=后面第一个是大写字母
已经有12人回复
-
为什么余额宝的年化利率越来越低？主要原因有哪些？
已经有4人回复
-
今天基金会出结果吗？20260819
已经有8人回复
» 本主题相关价值贴推荐，对您同样有帮助:
- 看看这个苦逼的人吧，文章竟然审稿11年？杂志linear algebra and its applications
已经有71人回复
- 一本不错的书Video Tracking: Theory and Practice
已经有7人回复
- RSC的杂志，拒稿重投（reject and resubmssion）还需要回复审稿人意见吗？
已经有6人回复
- European Food Research and Technology 投稿 多久会变成 Under Review 呢
已经有8人回复
- 求助：Materials Chemistry and Physics的word 模板
已经有5人回复
- 【求助】siesta输入文件中赝势文件的作用？
已经有8人回复
- Journal of Pharmaceutical and Biomedical Analysis投稿求助
已经有9人回复
- 【资源】Standard Handbook of Petroleum and Natural Gas Engin
已经有3人回复
- 【求助】the French Ministry of Education and Research
已经有14人回复
- Applied Microbiology and Biotechnology期刊好快 一天就under review
已经有10人回复
- 评论性论文被materials and design接收
已经有28人回复
- 求助journal of agricultrual and food chemistry 投稿问题
已经有7人回复
8楼2009-09-22 23:21:42
2楼2009-07-16 22:32:38
★ ★ ★
freshgirl(金币+1,VIP+0):谢谢参与~ 7-17 14:13
wuchenwf(金币+2,VIP+0):谢谢分享 12-3 21:57
freshgirl(金币+1,VIP+0):谢谢参与~ 7-17 14:13
wuchenwf(金币+2,VIP+0):谢谢分享 12-3 21:57
|
wuchenwf ，您好。 上面是在我学习ESPRESSO时被忽略的一个问题。 每次使用USP，我都采用了默认的ecutrho（既四倍的ecutwfc） 虽然GUI会提醒ecutrho没有设置，但是我没有做任何改动，直接计算。 后来才发现，norm-conserving时，ecutrho=4*ecutwfc是正确的设置 而USPS下，通常ecutrho=10*ecutwfc。而这个十倍是需要手动设置的 所以把自己的教训写在这里：） |
3楼2009-07-17 10:08:30
9楼2009-12-03 19:05:37
简单回复
2009-09-18 20:22
回复
