[gmx-users] coil-globule

[Dmitriy Golubobsky]

Dear Guru;
Please give any suggestion or hint on this problem
I do MD for a polymer chain (about 1000 atoms) in water (SPC) with OPLSAA
according to the alogoritm
1 em in vacoom
2. solvate with water
3. do em and position restrain
4. do NVT MD with berendsen thermostan
with dt=0.001ps and trajectory length 5ns
Coulomb, VdW=cut-off
rlist=1.2
r_coulomb=1.4
r_vdw=1.4

the aim of simulation is to find coil to globule transition
I do NVT under different temperatures (from 280 to 340 K)
and really find the temperature after what my polymer become a globule
(about 310 K)
it was the result that i expact =)
but when I do MD with the temperature 315-everything is ok,it is a globule,
320-ok.
but with the higher tempetature it's didn't become a globule. and it's not
what i'm expacting.

may be where is a mistake in my algorithm.
perhaps i've to do an annealing MD or something else?



-- 
Dmitriy Golubovsky
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