[QE-users] how to obtain random initial velocities with CP

[Eduardo Menendez]

Hi,
I am unable to start a MD with CP with random velocities setting an initial
temperature, using QE 6.3. Reading the input description I understood that
I could start it using              ion_velocities = 'random', tempw=
starting T. However, I always start with 0 temperature.

This is my output
&CONTROL
                 calculation = 'cp' ,
                restart_mode = 'restart' ,
                  pseudo_dir = './' ,
                        outdir='./tmp',
                        wfcdir='./tmp',
                        prefix='mapi',
                        nstep = 500,
                           dt = 4.13413733424,
            ndr = 51,
            ndw = 51,
            iprint =50,
            isave = 50,
/
&SYSTEM
                         ibrav=0,
                       celldm(1)=1.889726132885 ,
                          nat=768,
                        ntyp=5,
                        ecutwfc=35.0  ! 50,
                     ecutrho=200.0 ,  ! 180,
                    input_dft = 'pbesol',
              nr1b=21, nr2b=21, nr3b=21,  ! nr1b=(2*r_cut)/(Lx)*nr1
                          nbnd = 1700,
/
&ELECTRONS
                        conv_thr = 1.0e-5,
!  options for CP
            emass = 400.d0, ! default, Mosconi et al,PCCP 16,16137 (2014),
doi: 10.1039/C4CP00569D
            emass_cutoff = 2.5d0, ! default
            electron_dynamics = 'verlet' ,

/
 &IONS
                ion_dynamics = 'verlet' , !  'verlet' ,
!             ion_temperature = 'not_controlled',
             ion_velocities = 'random',
                       tempw = 600.0 ,
 /
&CELL
                cell_dynamics = 'none'
/
In the output I read
   Ionic position will be re-read from restart file
   All atoms are allowed to move
   Ionic temperature control via canonical velocities rescaling :
   temperature required =  600.00000K, tolerance =  100.00000K
......
  nfi     ekinc              temph  tempp     etot
enthal               econs                econt              vnhh
xnhh0   vnhp    xnhp0
      5    0.000002129555068    0.0    0.00  -12738.991035174058
-12738.991035174058  -12738.991033373713  -12738.991031244159   0.0000
0.0000   0.0000   0.0000
      6    0.000005713182507    0.0    0.00  -12738.991057915813
-12738.991057915813  -12738.991042309621  -12738.991036596439   0.0000
0.0000   0.0000   0.0000

nfi begins at 5 because there were 4 previous steepest descent dynamics
(ould I reset the nfi counter? ), which got the wfc from a PWSCF
self-consistent run.

Thanks,

Eduardo Menendez Proupin
University of Chile
www.gnm.cl/emenendez
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