[Pw_forum] Constraint on centre of mass of a molecule

[Ngoc Linh Nguyen]

Lorenzo Paulatto wrote:
> On Fri, 09 Apr 2010 06:38:50 +0200, siva rama krishna  
> <sivaramakrishnaj at gmail.com> wrote:
>   
>> Similarly, can we arrest the Z-component of the centre of mass of a  
>> molecule
>> ?
>>     
> Furthermore, if you put the molecule on teh substrate and it just breaks,  
> than the centre of mass would pretty much loose any meaning. 
Sometime, the molecules is physisorbed, only weak binding, to the 
substrate, and the molecule's dissociation has not happened yet. In that 
case, the diffusion of molecules will be presented, and it can be seen 
as a picture that the molecules are moving parallelly to the plane's 
substrate to find out the activate sites. And of course, the center of 
mass is not changed at all belong to Oz component.
Anyway, in the realistic case the mechanism of molecules is more 
complicated.
 

regards,

Linh


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