Dear Rajesh, Yes, AA is angstrom. Currently you can not use vc-relax. You can do a geometry optimization with fixed cell so you can use “relax". Regarding the positive total energy, first, you should try the ESM_example calculations and compare the results with the reference results. Did you get reasonable results? If yes, I can not understand the origin of your problem now.
Best regards, Minoru -------------------------------------------------------------------------------------------------------- Minoru Otani National Institute of Advanced Industrial Science and Technology Research Centre for Computational Design of Advanced Functional Materials email : [email protected]<mailto:[email protected]> --------------------------------------------------------------------------------------------------------- On Jul 26, 2017, at 21:14, Rajesh <[email protected]> wrote: 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]<mailto:[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]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> on behalf of Rajesh <[email protected]<mailto:[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]<mailto:[email protected]> http://pwscf.org/mailman/listinfo/pw_forum _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
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