Hi all, I've searched the email list archive and found this long discussion on calculating thermal conductivity using GK
method. Can someone explain to me why the Virial part was divided by 1.6021765e6, since the unit for each system is consistent,
including metal and real. What I dont know is the unit of Virial stress. Should it be the same as pressure*volume (so should be bar*A^3 if it is in metal unit)?
Steve may want to answer this.
Thanks, Ajing
>> compute PE all pe/atom
>> compute KE all ke/atom
>>
>> variable CX atom (vx[]*(c_KE[]+c_PE[]))
>> compute Jcx all reduce sum v_CX
>>
>> variable CY atom (vy[]*(c_KE[]+c_PE[]))
>> compute Jcy all reduce sum v_CY
>>
>> variable CZ atom (vz[]*(c_KE[]+c_PE[]))
>> compute Jcz all reduce sum v_CZ
>>
>> compute SA all stress/atom virial
>>
>> # J_x = S_xx*V_x + S_xy*V_y + S_xz*V_z
>> variable VX atom
>> -(c_SA[][1]*vx[]+c_SA[][4]*vy[]+c_SA[][5]*vz[])/1.6021765e6
>> compute Jvx all reduce sum v_VX
>> # J_y = S_yx*V_x + S_yy*V_y + S_yz*V_z, yx=xy
>> variable VY atom
>> -(c_SA[][4]*vx[]+c_SA[][2]*vy[]+c_SA[][6]*vz[])/1.6021765e6
>> compute Jvy all reduce sum v_VY
>> # J_z = S_zx*V_x + S_zy*V_y + S_zz*V_z, yx=xy
>> variable VZ atom
>> -(c_SA[][5]*vx[]+c_SA[][6]*vy[]+c_SA[][3]*vz[])/1.6021765e6
>> compute Jvz all reduce sum v_VZ
>>
>> variable Jx equal (c_Jcx+c_Jvx)
>> variable Jy equal (c_Jcy+c_Jvy)
>> variable Jz equal (c_Jcz+c_Jvz)
Can someone explain to me why the Virial part was divided by 1.6021765e6, since the unit for each system >is consistent, including metal and real. What I dont know is the unit of Virial stress. Should it be the same >as pressure*volume (so should be bar*A^3 if it is in metal unit)?
Real and metal units are not consistent, meaning you can not take any
2 quantities and
multiply them and get the same units as another quantity. Hence you often
need conversion factors. The units produced by any compute are
stated explicitly on the doc page for that compute.
Steve