the velocity of the particle is different from the results of visualization

zhj... at gmail.com zhj... at gmail.com
Thu Nov 10 11:06:27 CET 2016


OK, thaks, this is the MD section:

*&MOTION*
*&MD*

*&VELOCITY_SOFTENING*
*STEPS 30*
*ALPHA 0.2*
*DELTA 0.05*
*&END*

*DISPLACEMENT_TOL 40*
*ENSEMBLE NVT*
*STEPS 30000*
*TIMESTEP 0.5*
*TEMPERATURE 300*
*&THERMOSTAT*
*REGION GLOBAL*
*TYPE CSVR*
*#&NOSE*
*#LENGTH 6*
*#YOSHIDA 3*
*#MTS 2*
*#TIMECON 0.5*
*#&END NOSE*
*&CSVR*
*TIMECON 1*
*&END CSVR*
*&END THERMOSTAT*

*&PRINT*
*&ENERGY*
*&EACH*
*MD 1                                                                       
                                                                &END       
                                                                            
                                                    ADD_LAST NUMERIC       
                                                                            
                                        &END                               
                                                                            
                            &END PRINT                                     
                                                                            
                &END MD                                                     
                                                                            
   &PRINT                                                                   
                                                                            
                                                                            
                                  &TRAJECTORY ON                           
                                                                            
                      FILENAME ./Au_300K                                   
                                                                            
          FORMAT XYZ                                                       
                                                                        
  &EACH                                                                     
                                                                 MD 2       
                                                                            
                                                    &END EACH               
                                                                            
                                       &END TRAJECTORY                     
                                                                            
                           &END PRINT                                       
                                                                            
              &END MOTION*

As you can see, the program output the  trajectories every two MD steps 
(every 1 fs)

在 2016年11月10日星期四 UTC+8下午5:09:01,Vladimir Rybkin写道:
>
> Dear author,
>
> Generally, the particle will travel 0.4 angstrom in 1 fs if no forces act 
> on it (Newton's first law). In genaral, in atomistic systems the forces are 
> not zero.
> what was you time step? Could you provide the whole input (at least 
> $subsys and $MD)?
>
> Yours,
>
> Vladimir
>
> четверг, 10 ноября 2016 г., 9:38:23 UTC+1 пользователь zhj... at gmail.com 
> написал:
>>
>> Hi, all
>> In MD simulation, I give an Au particle the velocity of 0.42 
>> angstrom*fs^-1 by using CP2K_INPUT 
>> <https://manual.cp2k.org/cp2k-4_1-branch/CP2K_INPUT.html> / FORCE_EVAL 
>> <https://manual.cp2k.org/cp2k-4_1-branch/CP2K_INPUT/FORCE_EVAL.html> / 
>> SUBSYS 
>> <https://manual.cp2k.org/cp2k-4_1-branch/CP2K_INPUT/FORCE_EVAL/SUBSYS.html>
>>  / VELOCITY 
>> <https://manual.cp2k.org/cp2k-4_1-branch/CP2K_INPUT/FORCE_EVAL/SUBSYS/VELOCITY.html> . 
>> However, when I visualize the results, I found that this Au particle 
>> traveled a distance of about 4 angstrom in 1 fs.
>> So, can anyone tell me the reason?
>>
>>
>> Here, I post the parts of velocity setting:
>>
>> ......
>> &VELOCITY
>> PINT_UNIT angstrom*fs^-1
>> 0    0    0   
>> 0    0    0   
>> 0    0    0   
>> 0    0    0   
>> 0    0    0   
>> 0    0    0   
>> ......
>> ......
>> 0    0    0   
>> 0    0    0
>> 0    0    -0.41989  ## this is the velocity of Au particle
>> &END VELOCITY
>>
>
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