答复: damp parameter in”fix langevin command”

2011/4/7 XiaoJing <[email protected]>:

Thank you!
I have fixed the substrate, and use "fix nve" combining "fix langevin" to
control Temperature. If I only use "fix nve", how do I control temperature
of the upper-region near surface?

you don't. this is more realistic. nature doesn't use a thermostat either.

you first equilibrate your system with a thermostat, if you are careful you
do it first for a while with a shorter and then with a longer damp factor.

having the thermostat on the lower layer(s) above the fixed atoms
emulates the coupling of the surface to the bulk.

just think about this for a while and you'll see. trust me. :wink:

cheers,
   axel.

Thank you very much!
I see, I still have a question for disscusion: If the epitaxial layer is
growing, up to several nm thickness, the thermostat region is not changed.
That is to say, the thicker the growth film, the effect of the thermostat is
less, harder for the coupling of the surface to the bulk. Is that right?
Sorry for so many questions.
   Could I write some commands in the input file to control the thermostat
region under the surface?

-----邮件原件-----