Dear Minoru, Thanks for quick response. Here AA=angstrom?? I tried esm method in vc-relax calculations with two boundary conditions 1. pbc and 2. bc1.
For pbc conditions the energy comes out too be negative but for bc1 it was positive ( with no esm_w value). Energy of solids is always negative. So where I am wrong? Thanks. Rajesh On Wed, Jul 26, 2017 at 5:32 PM, 大谷実 <[email protected]> wrote: > Dear Rajesh, > > I can not fully understand your configuration. But let me suppose you have > a single graphene > sheet in a calculation cell with 15AA vacuum on both sides. > > L_z = 15AA + graphene sheet (0 AA) + 15AA = 30 AA > The graphene sheet is located at z=0. > > For bc1 calculation, you do not need to use esm_w. For bc2 or bc3, if you > want to put ESM(metal) electrode at the position of z= +/- 15AA (for bc2) > or z= +15AA (for bc3), esm_w = 0.0. The esm_w specifies the offset value of > the ESM(metal) electrode position from the cell edge (z=+/- L_z/2). Thus, > if you want to put the electrode on z= + 18AA, the esm_w must be 3AA. > > Best regards, > Minoru > ________________________________________ > From: [email protected] <[email protected]> on behalf > of Rajesh <[email protected]> > Sent: Wednesday, July 26, 2017 8:34:20 PM > To: PWSCF Forum > Subject: [Pw_forum] ESM method > > Dear Users, > > in the manual I find this "ESM region begins at z = +/- [L_z/2 + esm_w]". > Suppose I have graphene sheet of with 3.33Angstrom as its thickness and I > want to apply a 15Angstrom vacuum on both sides of the sheet. What are z > and L_z/2 here?? is L_z/2=3.33A?? and Then what will be the value of > position offset esm_w?? is esm_w=15angstrom?? and z=3.33+15+15=33.3 > Angstrom? Please explain. > > > Thank you. > > > > Rajesh > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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