It doesn't require symmetry: it requires NO symmetry. Which is actually the opposite of what you seem to think.
Kind regards -- Lorenzo Paulatto Written on a virtual keyboard with real fingers On 29 Jul 2017 2:14 p.m., "Robert Molt" <r.molt.chemical.phys...@gmail.com> wrote: > I appreciate the help. If ESM does not require this symmetry, can you > explain what is meant by the manual's statement of: > > : > > "Requires cell with a_3 lattice vector along z, > > normal to the xy plane, with the slab centered > around z=0. Also requires symmetry checking to be > disabled along z, either by setting nosym > <http://www.quantum-espresso.org/wp-content/uploads/Doc/INPUT_PW.html#nosym> > = .TRUE. > or by very slight displacement (i.e., 5e-4 a.u.) > of the slab along z." > > > > I want to make sure I am in compliance with the manual's specifications, > and I clearly must not understand what that means if I misinterpreted it to > mean it requires symmetry along the z axis. > > > Separately, given that we have no symmetry in xy, is it logically > necessary to "cap" boundary atoms with hydrogens (or the like) to avoid > artifacts at the boundary? > > > On 7/28/17 6:41 PM, 大谷実 wrote: > > Dear Robert, > > Besides Lorenzo’s message, I can add one more thing. ESM does not require > symmetry along z-axis, so you do not need to put an additional adsorbate > molecule on the bottom. > > Also requires symmetry checking to be >> disabled along z, either by setting nosym >> <http://www.quantum-espresso.org/wp-content/uploads/Doc/INPUT_PW.html#nosym> >> = .TRUE. >> or by very slight displacement (i.e., 5e-4 a.u.) >> of the slab along z. >> >> > > Best regard, > Minoru > ------------------------------------------------------------ > -------------------------------------------- > Minoru Otani > National Institute of Advanced Industrial Science and Technology > Research Centre for Computational Design of Advanced Functional Materials > email : minoru.ot...@aist.go.jp > ------------------------------------------------------------ > --------------------------------------------- > > On Jul 29, 2017, at 5:15, Lorenzo Paulatto <lorenzo.paula...@impmc.upmc. > fr> <lorenzo.paula...@impmc.upmc.fr> wrote: > > It does not matter, it is only need to be roughly centered > > -- > Lorenzo Paulatto > Written on a virtual keyboard with real fingers > > On 28 Jul 2017 9:36 p.m., "Dr. Robert Molt Jr." <r.molt.chemical.physics@ > gmail.com> wrote: > >> Good evening, >> >> I am confused by the "centering" requirements of ESM. It is stated that: >> >> Requires cell with a_3 lattice vector along z, >> normal to the xy plane, with the slab centered >> around z=0. Also requires symmetry checking to be >> disabled along z, either by setting nosym >> <http://www.quantum-espresso.org/wp-content/uploads/Doc/INPUT_PW.html#nosym> >> = .TRUE. >> or by very slight displacement (i.e., 5e-4 a.u.) >> of the slab along z. >> >> I have constructed a slab which is symmetric about the xy plane and >> centered around z=0 contour. This is fine and good. >> >> However, once I add the adsorbate molecule, I cannot have >> symmetry...unless it is intended that I add the same adsorbate molecule on >> the "bottom" of the simulation, too? I am unclear what is meant by the slab >> being "centered." Center of mass? Center of symmetry? >> >> >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum@pwscf.org >> http://pwscf.org/mailman/listinfo/pw_forum >> > _______________________________________________ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > > > > > _______________________________________________ > Pw_forum mailing > listPw_forum@pwscf.orghttp://pwscf.org/mailman/listinfo/pw_forum > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum >
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