Langevin dynamics was implemented many years ago in QE, but I have never heard of anybody using it, nor seen any evidence that it works (or that it doesn't).
Paolo On Mon, Aug 10, 2015 at 1:10 PM, Venkataramana Imandi < venkataramana.ima...@gmail.com> wrote: > Dear Sir/ Madam, > > I am using quantum espresso (version:5.1.2) for doing Langevin dynamics on > Ethene molecules were kept top and bottom of silver oxide surface (total > atoms: 37) running on Red Hat machine with serial and parallel process. In > the output file, the coordinates of some of the atoms getting starred(***). > In order to understand more about results, I tried with simple systems > containing 2 Si atoms, the results shows that Langevin dynamics is working > fine but the distance between two Si atoms goes on increasing (at the end > of 100 md steps, the distance is 560 Angstroms). Moreover, herein Langevin > dynamics is over-damped and the parameter of gamma (friction coefficient) > is not mentioned anywhere in the input file description of pw.x related > manual. Hence, I request you kindly suggest me how to perform Langevin > calculations on my original system. Input file and starred(**) coordinates > of my original system (output file) were attached. > > &control > calculation='md', > prefix='ag_eth', > dt=20.D0, > nstep=50, > etot_conv_thr=1.0D-6, > forc_conv_thr=1.0D-5, > pseudo_dir = '/home/venkat/ORR1/PPS1' > / > &system > ibrav=0, > nat=37, > ntyp=4, > ecutwfc = 30.0, > nosym=.true., > occupations='smearing', > smearing='m-p', > degauss=0.03, > tot_charge=1.0 > / > &electrons > electron_maxstep=2000, > diagonalization='david', > mixing_beta = 0.3, > conv_thr = 1.0D-6, > scf_must_converge=.false. > / > &ions > pot_extrapolation = 'second_order', > wfc_extrapolation = 'second_order', > ion_dynamics='langevin', > tempw=300.D0, > nraise=1 > / > ATOMIC_SPECIES > C 12.0107 C.pbe-rrkjus.UPF > H 1.00794 H.pbe-rrkjus.UPF > O 15.9994 O.pbe-rrkjus.UPF > Ag 107.8682 Ag.pbe-d-rrkjus.UPF > > CELL_PARAMETERS {angstrom} > 7.8980000000 0.0000000000 0.0000000000 > 0.0000000000 7.8980000000 0.0000000000 > 0.0000000000 0.0000000000 9.7479000000 > > ATOMIC_POSITIONS {angstrom} > > C 3.674759 2.942993 -3.493103 > H 4.121990 3.816735 -4.007690 > H 4.121990 2.069251 -4.007690 > C 2.211227 2.942993 -3.493103 > H 1.763996 3.816735 -4.007690 > H 1.763996 2.069251 -4.007690 > O 0.000000 0.000000 -2.719012 > Ag 4.448147 4.449893 -1.919012 > Ag 4.448147 1.436093 -1.919012 > Ag 1.437838 4.449893 -1.919012 > Ag 1.437838 1.436093 -1.919012 > Ag 2.942993 2.942993 0.000000 > Ag 2.942993 0.000000 0.000000 > Ag 0.000000 2.942993 0.000000 > Ag 0.000000 0.000000 0.000000 > Ag 1.437838 1.436093 1.919012 > Ag 1.437838 4.449893 1.919012 > Ag 4.448147 1.436093 1.919012 > Ag 4.448147 4.449893 1.919012 > O 0.000000 0.000000 2.719012 > C 3.674759 2.942993 3.493103 > H 4.121990 3.816735 4.007690 > H 4.121990 2.069251 4.007690 > C 2.211227 2.942993 3.493103 > H 1.763996 3.816735 4.007690 > H 1.763996 2.069251 4.007690 > O 0.000000 5.885983 -2.719012 > Ag 2.942993 5.885983 0.000000 > Ag 0.000000 5.885983 0.000000 > O 0.000000 5.885983 2.719012 > O 5.885983 0.000000 -2.719012 > Ag 5.885983 2.942993 0.000000 > Ag 5.885983 0.000000 0.000000 > O 5.885983 0.000000 2.719012 > O 5.885983 5.885983 -2.719012 > Ag 5.885983 5.885983 0.000000 > O 5.885983 5.885983 2.719012 > > K_POINTS {gamma} > > A BIT of OUTPUT FILE > > ATOMIC_POSITIONS (angstrom) > C 23.936881089 5.854758432 2.384283563 > H 5.319738992 3.101932011 -2.806230409 > H 5.032723666 3.366896985 -3.263624443 > C -19.193958442 -0.839672619 -8.633281572 > H 2.840673809 3.320817821 -3.598829264 > H 2.259010092 3.506469010 -4.024573435 > O 3.200827481 3.891444136 -5.674056522 > Ag -2.799093034 8.698187934 0.392246441 > Ag 6.216802688 0.615454519 -1.827886947 > Ag -1.094861601 5.714331653 -3.826763750 > Ag -0.821908140 -7.523290040 -8.937996255 > Ag 7.394141127 8.391763262 7.199208896 > Ag 66.2293865871065.326804153 192.584344197 > Ag 4515.057117298 369.600932228 188.645687521 > Ag 395.079974228 976.555500510 23.641381229 > Ag -0.868373165 1.254442767 -0.725095564 > Ag 0.598543920 4.290748028 1.130598433 > Ag 3.451303546 0.003835176 -2.147641351 > Ag 4.967046204 4.664900169 1.274377193 > O 4.154896086 3.538399188 4.404896973 > C 399.041692489-175.281493613-563.071390643 > H 3.281002088 3.892508380 4.191590229 > H 5.590682748 1.083007852 4.528641700 > C -206.161786136-122.423501782 -55.021382542 > H 0.246549207 5.329189077 3.491183253 > H 1.659499381 1.418695757 3.087580955 > O -19.384256566 28.168644116 11.242605036 > Ag -75.320660159**************-197.570811974 > Ag 561.119359654-921.736664610 96.273929826 > O 0.652654857 4.794099697 2.674333108 > O 0.725736992 1.497121799 -3.145265492 > Ag ************** -53.851744674 435.559732159 > Ag -59.3881630261875.893021868 -68.801534006 > O 4.092070388 0.327775217 7.087480811 > O 1.475113672 4.942700103 -3.552674785 > Ag -847.347981606************** -58.746720826 > O 5.344579864 2.986191369 5.581658260 > > > > Best, > Venkataramana > PhD student > > > -- > venkataramana > > _______________________________________________ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > -- Paolo Giannozzi, Dept. Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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