<div>Hi, all</div>
<div> </div>
<div>There are some things confusing and resulting in error when I run mdrun for energy minization and md.</div>
<div> </div>
<div>I use Gromacs 4.0.4 to simulate electroosmotic flow in slab geometry with only 2 dimensional </div>
<div>periodic boundary (x and y), the system is aqueous solution with some ions, eg. CL- and Na+,</div>
<div>flowing through a plate channel, with external electrical field applied along x-direction, the height of channel</div>
<div>is z-direction. </div>
<div> </div>
<div>Coulomb interactions are computed with PME, and use pbc=xy, after running EM, all ouput tpr box sizes </div>
<div>in z-direction becomes zero, eg. originally the box size is 4.50000,4.50000,3.90000, after EM, it became</div>
<div>4.50000,4.50000,0.00000. so I can't use the output gro of EM for the MD run.</div>
<div> </div>
<div>Did someone encounter this before and can give me some suggestion for my mdp setup?</div>
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<div>Thanks in advance.</div>
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<div>(sorry for bad English expressions)</div>
<div> </div>
<div>some options for mdp file of mine are here:</div>
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<div>pbc = xy</div>
<div>rlist = 1.1 </div>
<div>rcoulomb = 1.1 <br>rvdw = 1.1 </div>
<div> </div>
<div>; electrostatics<br>coulombtype = PME </div>
<div>fourierspacing = 0.12 </div>
<div>;fourier_nx = </div>
<div>;fourier_ny = <br>fourier_nz = 30<br>pme_order = 4 <br> dim</div>
<div>ewald_geometry = 3dc ; IMPORTANT</div>
<div>optimize_fft = yes ; </div>
<div> </div>
<div>nwall = 2 <br>wall_type = 10-4 <br>;wall_r_linpot = <br>wall_atomtype = SI SI <br>wall_density = 7.12 7.12 <br>
wall_ewald_zfac = 3 </div>
<div> </div>
<div>; NEMD<br>acc_grps = WA WAb WAu<br>accelerate = 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0<br>freezegrps = WA WAb WAu<br>freezedim = Y Y Y Y Y Y Y Y Y<br>
</div>
<div>; Electric fields <br>E_x = 1 -0.55 0</div>
<div></div>
<div> </div>
<div><br clear="all">Regards,<br>Yinhe Zhang<br></div>