[Pw_forum] Should we use a double bond or 2 H atoms to saturate the system?

[Hongsheng Zhao]

Dear All,

This issues is somehow not so pertained to the PWSCF, but a gerneral DFT modelling problem, sorry for this request on this list. 

We all know that the H atoms is often used to saturate the dangling bonds in the system's edge, say, for graphene nanoribbon.  My issue is: as far as the passivation results is concerned, adding 2 atoms is equivalent to introduce a double bond between the two adjacent ions in the system, am I right?  If so, Should we use a double bond or 2 H atoms to saturate the system?

Regards.
-- 
Hongsheng Zhao <zhaohscas at yahoo.com.cn> 
School of Physics and Electrical Information Science, 
Ningxia University, Yinchuan 750021, China
GnuPG DSA: 0xD108493
2011-4-25