[Pw_forum] Langevin dynamics
Paolo Giannozzi
p.giannozzi at gmail.com
Sat Aug 15 11:24:26 CEST 2015
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.imandi at 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 at 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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20150815/824bc5dc/attachment.html>
More information about the users
mailing list