yes，I have just made a lapse of the pen.I also want to know if strain energy lists anywhere after the calculation in Siesta.Thanks very much. Dexi Shao
2014-07-21 21:20 GMT+08:00 Максим Арсентьев <[email protected]>: > MD.VariableCell false means internal geom. optimization with cell > parameters fixed and geom. opt. of internal coordinates of atoms only > MD.VariableCell true means full geom. optimization (geom. opt. of both > internal coordinates of atoms and cell parameters) > so when using MD.VariableCell false cell parameters are fixed > > > > 2014-07-21 17:06 GMT+04:00 邵德喜 <[email protected]>: > > What do you mean full opt here? And I can not understand " full opt. >> with this option "true" cell parameters will be the same". >> In my opnion, cell parameters will be change with MD.VariableCell >> being false in the structual optimazition. >> >> >> 2014-07-21 20:10 GMT+08:00 Максим Арсентьев <[email protected]>: >> >> When you perform internal optimization with MD.VariableCell false, cell >>> parameters are fixed, so if you further perform full opt. with this option >>> "true" cell parameters will be the same. So in both these cases cell >>> parameters are the same and you should chose the same kgrig_Monkhorst_Pack >>> block and Briollin zone will not change when you transfer from internal to >>> full geom. optim. >>> >>> >>> 2014-07-21 15:38 GMT+04:00 Kanhao Xue <[email protected]>: >>> >>> It is strange argument. When the cell parameter changes, the Brillouin >>>> zone will change, therefore the Monkhost-Pack K points will change their >>>> locations. However, one is just concerned with the rough density of K >>>> points in this scheme. Why one cannot use Monkhorst-Pack? >>>> >>>> >>>> On Mon, Jul 21, 2014 at 11:48 AM, 邵德喜 <[email protected]> wrote: >>>> >>>>> I was told that when MD.VariableCell is setted True, then we can >>>>> not use block kgrid_Monkhorst_Pack option . >>>>> Thanks very much . >>>>> >>>>> >>>>> 2014-07-21 15:31 GMT+08:00 Максим Арсентьев <[email protected]>: >>>>> >>>>> You right, you should perform 2 structural relaxations. Before doing >>>>>> this do calculations without geom. optim. with different density of >>>>>> kpoints >>>>>> by "%block kgrid_Monkhorst_Pack" and see convergence of kpoint density on >>>>>> forces. This also should be checked for meshcutoff - convergence in >>>>>> forces >>>>>> is very important for geom. optim. >>>>>> >>>>>> >>>>>> 2014-07-21 6:59 GMT+04:00 邵德喜 <[email protected]>: >>>>>> >>>>>> Thanks very much. >>>>>>> Do you mean that I should do structual relaxation twice?First with >>>>>>> MD.VariableCell >>>>>>> False,then with MD.VariableCell True? >>>>>>> If I could just do structual relaxation once with MD.VariableCell >>>>>>> True? And if " kgrid Monkhorst Pack" option can be reserved at >>>>>>> the same time? >>>>>>> Yours Sincerely! >>>>>>> Dexishao >>>>>>> >>>>>>> >>>>>>> 2014-07-21 4:55 GMT+08:00 Максим Арсентьев <[email protected]>: >>>>>>> >>>>>>> Dear, Dexi! >>>>>>>> >>>>>>>> You can vary residual strain by MD.MaxStressTol. >>>>>>>> Use CG, relax with MD.VariableCell False first, then input >>>>>>>> coordinates obtained to a new file with MD.VariableCell True. >>>>>>>> Note you may need to shift some atoms manually before geometry >>>>>>>> optimization: if all atoms are in 2D plane, then all of them will >>>>>>>> remain in >>>>>>>> plane after geom. optim. because z forces are zero, so you need to >>>>>>>> shift >>>>>>>> any atom to unlock z forces and avoid such a false state. >>>>>>>> >>>>>>>> >>>>>>>> 2014-07-20 4:01 GMT+04:00 邵德喜 <[email protected]>: >>>>>>>> >>>>>>>> Dear everyone: >>>>>>>>> I really want to know how to get a structure wuthout strain.For >>>>>>>>> example ,Let's consider graphene ,I get the structure from materials >>>>>>>>> studio,and use it as initial one for siesta structual relaxation. >>>>>>>>> If in the relaxation set some options as follows: >>>>>>>>> MD.TypeOfRun CG/Verlet >>>>>>>>> MD.VariableCell True >>>>>>>>> ... >>>>>>>>> At the same time ,I replace " kgrid Monkhorst Pack" option with >>>>>>>>> k-grid cutoff. >>>>>>>>> When the relaxation is done,I want to ask if the final structure >>>>>>>>> after relaxation is >>>>>>>>> one structure without strain? >>>>>>>>> In general ,how to get a structure without strain is what I care. >>>>>>>>> Thanks in advance. >>>>>>>>> Dexi Shao >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> Best wishes, >>>>>>>> Maxim Arsent'ev, D.Sc.(Chemistry) >>>>>>>> Laboratory of research of nanostructures >>>>>>>> Institute of Silicate Chemistry of RAS >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Best wishes, >>>>>> Maxim Arsent'ev, D.Sc.(Chemistry) >>>>>> Laboratory of research of nanostructures >>>>>> Institute of Silicate Chemistry of RAS >>>>>> >>>>> >>>>> >>>> >>>> >>>> -- >>>> >>>> Sincerely yours, >>>> Kanhao Xue >>>> >>>> Laboratoire de Réactivité et Chimie des Solides (LRCS) >>>> UMR CNRS 7314 >>>> Université de Picardie Jules Verne >>>> 33 Rue Saint Leu, 80039 Amiens Cedex, France >>>> >>> >>> >>> >>> -- >>> Best wishes, >>> Maxim Arsent'ev, D.Sc.(Chemistry) >>> Laboratory of research of nanostructures >>> Institute of Silicate Chemistry of RAS >>> >>> >>> -- >>> Best wishes, >>> Maxim Arsent'ev, D.Sc.(Chemistry) >>> Laboratory of research of nanostructures >>> Institute of Silicate Chemistry of RAS >>> >>> >> > > > -- > Best wishes, > Maxim Arsent'ev, D.Sc.(Chemistry) > Laboratory of research of nanostructures > Institute of Silicate Chemistry of RAS >
