Temperature increasing




I just followed your suggestion and used nve ensemble.



But It didnt work properly.



I still have same problem.







Now I have one question.



Can you explain me the relation between applying rotational velocity and abnormal temperature increasing?



When I removed the command for applying rotational velocity, temperature was not increased.



So I guess that rotational velocity command casuses this problem. (fix 12 in my input file)







Best regards.









--------- 원본 메일 ---------


> 보낸사람: Andrew Jewett <[email protected]…24…>
> 받는사람 : 윤홍민 <[email protected]…1333…>
> 참조 : [email protected]
> 날짜: 2012년 5월 31일 목요일, 04시 22분 27초 +0900
> 제목: Re: [lammps-users] Temperature increasing
>
> I see one problem. You probably want to put a “fix nve” command after
> the “fix langevin” command.
> I have been using this:
>
> fix fxlan all langevin 300.0 300.0 1000.0 48279
> fix fxnve all nve
>
> (This is explained at
> http://lammps.sandia.gov/doc/fix_langevin.html)
>
> If that does not fix it, try reducing the complexity of your system
> and your input file and see when the problem goes away. (It looks
> like you already reduced the timestep.)
> Good luck.
>
> On Wed, May 30, 2012 at 12:31 PM, 윤홍민 <[email protected]…1333…> wrote:
> >
> > Hi all.
> >
> > My name is Hong Min
> > I want to simulate graphene.
> > But its temperature increased dramatically and converged at abnormal value.
> > I dont know what the problem is.
> >
> >
> >
> > I attach my input file and logfile below.
> >
> >
> >
> > -------------input---------------------------------
> >
> > dimension 3
> > boundary p p p
> > lattice sc 0.1
> > processors 8 1 1
> >
> > units metal
> >
> > atom_style charge
> > read_data data.graphene_rotation_run2
> >
> > pair_style airebo 2.6 1 0
> > pair_coeff * * CH.airebo C
> >
> > ####################### groups / variables ###############################
> > group bottom id <= 1008
> > group upper id <> 1009 1032
> >
> > group control_x1 id = 1033
> > group control_x2 id = 1034
> > group control_y1 id = 1035
> > group control_y2 id = 1036
> >
> > group control union control_y1 control_x1 control_y2 control_x2
> > group U_C union upper control
> >
> > neigh_modify exclude group control bottom exclude group control upper
> >
> > #displace_atoms upper move 3.684 17.725 0.0 units box
> >
> > variable x equal xcm(upper,x)
> > variable y equal xcm(upper,y)
> > variable z equal xcm(upper,z)
> > variable fx equal fcm(upper,x)
> > variable fy equal fcm(upper,y)
> > variable fz equal fcm(upper,z)
> > variable fsx_y1 equal f_6[1]
> > variable fsy_y1 equal f_6[2]
> > variable fsz_y1 equal f_6[3]
> > variable fs_y1 equal f_6[4]
> > variable fsx_x1 equal f_7[1]
> > variable fsy_x1 equal f_7[2]
> > variable fsz_x1 equal f_7[3]
> > variable fs_x1 equal f_7[4]
> > variable fsx_y2 equal f_8[1]
> > variable fsy_y2 equal f_8[2]
> > variable fsz_y2 equal f_8[3]
> > variable fs_y2 equal f_8[4]
> > variable fsx_x2 equal f_9[1]
> > variable fsy_x2 equal f_9[2]
> > variable fsz_x2 equal f_9[3]
> > variable fs_x2 equal f_9[4]
> >
> > ####################### velocity / fix ###############################
> >
> > velocity all create 10.0 102486 mom yes rot yes dist gaussian units box
> >
> > fix 1 upper npt temp 10.0 10.0 1.0 iso 1.01325 1.01325 10.0
> > fix 2 all langevin 10.0 10.0 1.0 699483
> > fix 4 control momentum 1 linear 1 1 1
> > fix 5 upper addforce NULL NULL -0.6491
> >
> > fix 6 control_y1 spring couple upper 0.5 0 0 -1 INIT
> > fix 7 control_x1 spring couple upper 0.5 0 0 -1 INIT
> > fix 8 control_y2 spring couple upper 0.5 0 0 -1 INIT
> > fix 9 control_x2 spring couple upper 0.5 0 0 -1 INIT
> >
> > fix 10 control momentum 1 linear 1 1 1
> >
> > neigh_modify every 1 check yes
> >
> > ####################### output ###############################
> >
> > dump 1 all atom 100 dump_rotation_run2.gra
> >
> > thermo 100
> > thermo_style custom step ke pe etotal temp press
> >
> > timestep 0.00001
> >
> > run 10000
> > ####################### run2 ###############################
> >
> > fix 12 control move rotate 9.824 25.524 8.14 0 0 1 0.000001 units box
> > run 400000000
> > write_restart restart.graphene_rotation_run2
> >
> >
> >
> > -------------------logfile-------------------------------------------------------------
> >
> > KinEng PotEng TotEng Temp
> > 1.337843 -7783.07 -7781.73 10
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> > 3.44E+12 -0.00014 3.44E+12 2.57E+13
> >
> >
> >
> >
> >
> >
> >
> >
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