应《网络安全法》要求，自2017年10月1日起，未进行实名认证将不得使用互联网跟帖服务。为保障您的帐号能够正常使用，请尽快对帐号进行手机号验证，感谢您的理解与支持！

24小时热门版块排行榜    

小木虫论坛-学术科研互动平台 » 计算模拟区 » 第一性原理 » Vasp&MedeA » 【求助完毕】NEB过渡态计算neb.dat中force的正负是什么意思？
21/1返回列表
查看: 642  |  回复: 1
只看楼主 @他人 存档 新回复提醒 (忽略) 收藏    在APP中查看

cenwanglai

荣誉版主 (知名作家)

[交流] 【求助完毕】NEB过渡态计算neb.dat中force的正负是什么意思？

这是我在官网论坛上提的问题（http://theory.cm.utexas.edu/foru ... 27&p=2933#p2933），请教！
I have got a neb.dat read like below:
0 0.000000 0.000000 -0.010838 0
1 0.867271 -0.837088 -1.279897 1
2 1.768503 -1.026423 -1.128849 2
3 2.584773 -0.937171 -2.621561 3
4 3.429818 -0.846114 -0.975741 4
5 4.433803 -1.987181 -2.796546 5
6 5.509804 -2.035966 -3.951533 6
7 6.561177 -2.989551 0.890184 7
8 7.546694 -2.312575 -0.077526 8

(1)What does a positive or a negative force item mean in the fourth column? Do the plus or minus sign directs the movement of the images?

(2)The distance between two nearby images is supposed to be lower than 1 Angstrom?

(3)Can anyone give me some advice about the 7th line with the lowest energy? The 8th line has been relaxed to ground state and is supposed to be CO-adsorbed-slab Final State. And the first line stands for configuration that CO in the vacuum off the slab surface.

[ Last edited by cenwanglai on 2011-3-19 at 15:27 ]
回复此楼

» 猜你喜欢

» 本主题相关价值贴推荐，对您同样有帮助:

» 抢金币啦！回帖就可以得到:

查看全部散金贴
1楼 2011-03-07 10:47:11
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

cenwanglai

荣誉版主 (知名作家)
★ ★
zzy870720z(金币+2): 谢谢总结 2011-03-19 16:42:51
I got a response from graeme:

It is a little tricky to see what's going on from a list of numbers, but here's a guess.

There does not appear to be a barrier for adsorption on the surface since the energy decreases from image 0->2. We typically use the NEB to find pathways between stable states. There may be a local minimum near image #2, but there is certainly a more stable adsorption geometry near image #7 which should be minimized.

Then, consider what you are trying to calculate. If there is no barrier for adsorption, this band may only tell you that the energy drops as you go from CO in vacuum to CO on the surface. If that is the case, there is no need for finding a minimum energy pathway.

Column 4 is the force projected along the band. A negative force means that the energy is going down along the band and a positive force means that it is going up.

The distance between images can be smaller than 1 Ang. If you used twice the number of images to represent the same band, the distance between images will decrease by a factor of two. In the limit of many images, that distance between images can be arbitrarily small. There are no interatomic interactions between images along the band.

[ Last edited by cenwanglai on 2011-3-19 at 15:32 ]
赞一下(1人) 回复此楼
2楼2011-03-19 15:29:54
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
相关版块跳转 我要订阅楼主 cenwanglai 的主题更新
21/1返回列表
普通表情 龙 兔 虎 猫 高级回复 (可上传附件)
信息提示
关闭
请填处理意见
关闭