Dear QE users, I am running MD with cp.x and I am trying to observe the trajectory of a molecule detaching from nickel-doped graphene surface.
It started with the molecule attached to the nickel atom in graphene sheet, electron minimization and ionic minimization in cp.x completed successfully. I then added a small random displacement to the system. When this is done. I added the followings to my input files, tempw increased from 100K to 200K then 300K. I have set dt=1.0d0, which is the smallest time step I can get. &ELECTRONS emass = 400.d0 , emass_cutoff = 2.5d0 , electron_dynamics = 'verlet' , / &IONS ion_dynamics = 'verlet' , ion_temperature = 'nose' , fnosep = 40.0 , tempw = 100.0 , / Each temperature was set to run for 10,000 time steps (100K, followed by 200K, then 300K with 'restart') which I believe equals to 0.24 fs. This is insufficient to obtain the trajectory, so I extended the 300K case to 50,000 time steps to get to 1.2 ps. But, cp.x failed at middle at about 18,000 time step, complaining maximum number of iteration is reached. I took a look at the .evp file and I saw the very last three lines produced strange numbers. # nfi time(ps) ekinc T_cell(K) Tion(K) etot enthal econs econt Volume Pressure(GPa) 17920 4.334641E-01 4.408245E-01 0.000000E+00 2.906500E+02 -736.06724803 -736.06724803 -735.93194407 -665.53445700 3.183024E+04 0.82843 17930 4.337060E-01 4.413418E-01 0.000000E+00 2.931947E+02 -736.06864256 -736.06864256 -735.93215404 -665.53398181 3.183024E+04 0.80824 17940 4.339478E-01 4.415645E-01 0.000000E+00 2.960657E+02 -736.07019548 -736.07019548 -735.93237041 -665.53381758 3.183024E+04 0.79642 17950 4.341897E-01 4.415359E-01 0.000000E+00 2.998132E+02 -736.07295464 -736.07295464 -735.93338506 -665.53470772 3.183024E+04 0.86277 17960 4.344316E-01 4.419086E-01 0.000000E+00 3.037218E+02 -736.07463932 -736.07463932 -735.93325017 -665.53404513 3.183024E+04 1.19960 17970 4.346735E-01 4.442741E-01 0.000000E+00 3.066442E+02 -736.07570387 -736.07570387 -735.93295428 -665.53122014 3.183024E+04 3.46370 17980 4.349154E-01 5.721941E-01 0.000000E+00 3.111465E+02 -736.07787056 -736.07787056 -735.93302506 -665.40319056 3.183024E+04 22.55459 It seems the ekinc and pressure increased suddenly and the system became destabilized. How can I resolved the problem? Thanks, Rolly -- PhD. Research Fellow, Dept. of Physics & Materials Science, City University of Hong Kong Tel: +852 3442 4000 Fax: +852 3442 0538 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
