Re: [SIESTA-L] MD.VariableCell and routine constr issue
Hi use GeometryConstraints fore example %block GeometryConstraints cellside c cellangle alpha beta gam position from -1 to -10 rigid 1 2 center 1 2 0.0 0.0 1.0 stress 4 5 6 routine constr %endblock GeometryConstraints On Sun, Jun 15, 2014 at 1:04 AM, xu yuehua xu11249...@gmail.com wrote: Hi,all: i want to relax the geometry of the cell, but i only need relax the c cellside, and fix the a, b side. according to the manual; i rewrite the cinstr.f the code is *! and J.M.Soler, 1996-2006.* *! * *! Use of this software constitutes agreement with the full conditions* *! given in the SIESTA license, as signed by all legitimate users.* *!* *c $Id: constr.f,v 1.6 2003/06/23 09:46:16 ordejon Exp $* * subroutine constr( cell, na, isa, amass, xa, stress, fa, ntcon )* *c ** *c User-written routine to implement specific geometric constraints,* *c by orthogonalizing the forces and stress to undesired changes.* *c Arguments:* *c real*8 cell(3,3): input lattice vectors (Bohr)* *c integer na : input number of atoms* *c integer isa(na) : input species indexes* *c real*8 amass(na): input atomic masses* *c real*8 xa(3,na) : input atomic cartesian coordinates (Bohr)* *c real*8 stress( 3,3) : input/output stress tensor (Ry/Bohr**3)* *c real*8 fa(3,na) : input/output atomic forces (Ry/Bohr)* *c integer ntcon: total number of positions constr. imposed* *c ** * implicit none* * integer na, isa(na), ntcon* * double precision amass(na), cell(3,3), fa(3,na),* * . stress(3,3), xa(3,na)* *c Write here your problem-specific code.* * stress(1,2) = 0.0d0* * stress(1,3) = 0.0d0* * stress(1,1) = 0.0d0* * stress(2,1) = 0.0d0* * stress(2,2) = 0.0d0* * stress(2,3) = 0.0d0* * stress(3,1) = 0.0d0* * stress(3,2) = 0.0d0* *c stress(3,3) = 0.0d0* * return* * end* am i right? my question is in the fdf input file, Should i set the MD.VariableCell =T and also Set %block GeometryConstraints routine constr %endblock GeometryConstraints or set the latter only, let the MD.VariableCell =F i need your help thanks very much! -- unl chemistry department
Re: [SIESTA-L] Cohesive Energy
It can be calculated as follows:
Cohesive energy = {total energy of the system - total number of atoms x (sum of
energy of its constituents in atomic state)}/total number of atoms
With Regards
Arun Kumar
Assistant Professor
Deptt of Physics
Govt College Banjar
Kullu
Himachal Pradesh
India
On Sunday, 15 June 2014, 11:48, Suman Chowdhury sumanchowdhur...@gmail.com
wrote:
Dear siesta user,
How to calculate cohesive energy from siesta output file for a particular
system?
--
Junior research fellow
Dept. of Physics,
University of Calcutta
Kolkata- 79, West Bengal, India.
Ph no-+91-9830512232
Re: [SIESTA-L] MD.VariableCell and routine constr issue
thank for your reply, but cellside: fixes the unit-cell side lengths to their initial values (not implemented yet). cellangle: xes the unit-cell angles to their initial values (not implemented yet). so my meaning 1. is that my consstr.f is right or not: 2. should i use MD.VariableCell =T ans well as the %block GeometryConstraints at the same time? On Sun, Jun 15, 2014 at 2:44 AM, Mostafa Shabani mostafa.nanophys...@gmail.com wrote: Hi use GeometryConstraints fore example %block GeometryConstraints cellside c cellangle alpha beta gam position from -1 to -10 rigid 1 2 center 1 2 0.0 0.0 1.0 stress 4 5 6 routine constr %endblock GeometryConstraints On Sun, Jun 15, 2014 at 1:04 AM, xu yuehua xu11249...@gmail.com wrote: Hi,all: i want to relax the geometry of the cell, but i only need relax the c cellside, and fix the a, b side. according to the manual; i rewrite the cinstr.f the code is *! and J.M.Soler, 1996-2006.* *! * *! Use of this software constitutes agreement with the full conditions* *! given in the SIESTA license, as signed by all legitimate users.* *!* *c $Id: constr.f,v 1.6 2003/06/23 09:46:16 ordejon Exp $* * subroutine constr( cell, na, isa, amass, xa, stress, fa, ntcon )* *c ** *c User-written routine to implement specific geometric constraints,* *c by orthogonalizing the forces and stress to undesired changes.* *c Arguments:* *c real*8 cell(3,3): input lattice vectors (Bohr)* *c integer na : input number of atoms* *c integer isa(na) : input species indexes* *c real*8 amass(na): input atomic masses* *c real*8 xa(3,na) : input atomic cartesian coordinates (Bohr)* *c real*8 stress( 3,3) : input/output stress tensor (Ry/Bohr**3)* *c real*8 fa(3,na) : input/output atomic forces (Ry/Bohr)* *c integer ntcon: total number of positions constr. imposed* *c ** * implicit none* * integer na, isa(na), ntcon* * double precision amass(na), cell(3,3), fa(3,na),* * . stress(3,3), xa(3,na)* *c Write here your problem-specific code.* * stress(1,2) = 0.0d0* * stress(1,3) = 0.0d0* * stress(1,1) = 0.0d0* * stress(2,1) = 0.0d0* * stress(2,2) = 0.0d0* * stress(2,3) = 0.0d0* * stress(3,1) = 0.0d0* * stress(3,2) = 0.0d0* *c stress(3,3) = 0.0d0* * return* * end* am i right? my question is in the fdf input file, Should i set the MD.VariableCell =T and also Set %block GeometryConstraints routine constr %endblock GeometryConstraints or set the latter only, let the MD.VariableCell =F i need your help thanks very much! -- unl chemistry department -- lalala lalala
