hello all,

i am doing simulation for aluminium.I intitially heated crystal uoto 800K. now what i need to do is to create two group.Then heat one group to temperature higher than

the melting temperature and keep the other group atoms fixed.

i need to heat such that its x and y dimension remain unchanged. so i applled barostate in z direction only.But as i know that barostate is applied to whole system.

so how can i correct the barostate.?

To apply thermostat to group i used fix_modify and to fix atoms of other group, i exclude it from time integration. i thought that i should turn off solid group interaction

so i used neigh_modify command .

can anyone please tell me neigh_modify can correct barostat or not?

I am writing script here.i observed that the temperature of group which is heated suddenly increse from 800K to 1200K and then decrese slowely during inital timesteps.

But if i run same script made for alumina then there is no any increase in themperature is observed.sO Is there any difference between this? please look the below script

and tell me what did i do wrong.

i named the heating group as liquid and fix group as solid.

region box block -0.15 20.5 -0.135 20.5 19.0 40.9 units box

read_restart stage1.restart.130000

region box1 block -0.15 20.5 -0.135 20.5 -0.2 19.0 units box

region box2 block -0.15 20.5 -0.135 20.5 19.0 40.9 units box

group solid region box1

group liquid region box2

#potential

pair_style eam/alloy

pair_coeff * * Al.in Al

compute 1 all pe

variable pressure equal press

variable peatom equal (pe/atoms)

variable mass_g equal mass(all)/6.02e23

variable vol_cm3 equal vol*1.0e-24

variable density equal v_mass_g/v_vol_cm3

variable teatom equal (etotal/atoms)

compute le liquid pe/atom

compute lo liquid reduce sum c_le

variable leatom equal (c_lo)/(960)

compute se solid pe/atom

compute so solid reduce sum c_se

variable seatom equal (c_so)/(960)

compute t_s solid temp

compute t_l liquid temp

compute te all temp

#compute p_l liquid pressure NULL

#pressure in solid

compute s1 solid stress/atom NULL

compute ps solid reduce/region box1 sum c_s1[1] c_s1[2] c_s1[3]

variable solidpress equal -(c_ps[1]+c_ps[1]+c_ps[1])/(3*20*17*26)
variable sxx equal -(c_ps[1])/(20*17

*26)*

variable syy equal -(c_ps[2])/(2017

variable syy equal -(c_ps[2])/(20

*26)*

variable szz equal -(c_ps[3])/(2017*26)

variable szz equal -(c_ps[3])/(20

#pressure in liquid

compute l1 liquid stress/atom NULL

compute pl liquid reduce/region box2 sum c_l1[1] c_l1[2] c_l1[3]

variable liquidpress equal -(c_pl[1]+c_pl[1]+c_pl[1])/(3*20*17*26)
variable lxx equal -(c_pl[1])/(20*17

*26)*

variable lyy equal -(c_pl[2])/(2017

variable lyy equal -(c_pl[2])/(20

*26)*

variable lzz equal -(c_pl[3])/(2017*26)

variable lzz equal -(c_pl[3])/(20

thermo_style custom step c_t_s c_t_l temp press v_sxx v_syy v_szz v_lxx v_lyy v_lzz pxx pyy pzz v_leatom v_seatom lz

neigh_modify exclude group solid solid

restart 150000 stage2.restart

log log.heat1500

fix 3 liquid npt temp 800 1500 1.0 z 0.0 0.0 1.0 dilate liquid

fix_modify 3 temp t_l

run 70000

unfix 3