It depends upon your system. In a dynamics on the electronic ground state
("Born-Oppenheimer" MD) your time step dt should be smaller than a fraction
(let us say 1/10) of the inverse of the highest phonon frequency.On Tue, Jan 15, 2019 at 11:38 AM LEUNG Clarence <[email protected]> wrote: > Dear Giuseppe, > > Thanks for your suggestion. > Can MD in pw.x perform the simulation with dt = 1 fs ? > > LIANG Xiongyi > ------------------------------ > *发件人:* users <[email protected]> 代表 Giuseppe > Mattioli <[email protected]> > *发送时间:* 2019年1月15日 17:35 > *收件人:* [email protected] > *主题:* Re: [QE-users] error in cp.x > > > Dear Liang Xiongyi > > There are a few things that should be changed in your input: for > example dft-d3 is not implemented in cp.x., and nr(i)b=16 is a bit on > the strict side (I generally use 20, but you should be sure that your > value is insensitive to further change). However, dt=1 fs is a huge > jump for CPMD and this is possibly the source of your > orthonormalization error. You may try to use dt=1 a.u. for electronic > minimization, and dt=3-6 a.u. for finite temperature runs. If you want > to speed-up electronic minimization, then use pw.x and read the > instructions for cp.x-pw.x interoperability to start a finite > temperature CPMD from a ground state obtained by using pw.x. Remember > also that, AFAIK, cppp.x is currently not usable for QE 6.3. You > should write your own tool to analyze trajectories, as the prefix.pos > output is written in a.u., too. > HTH > Giuseppe > > LEUNG Clarence <[email protected]> ha scritto: > > > Dear QE Users, > > > > When I use the cp.x to perform the thermal stability with dt = 1 fs, > > an error occur: > > > > > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > > Error in routine ortho (1): > > ortho went bananas > > > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > > > > stopping ... > > > > And I have try to use short dt, it can works. > > > > The input file is followed: > > > > &CONTROL > > etot_conv_thr = 3.5D-6 , > > forc_conv_thr = 4.0D-4 , > > ekin_conv_thr = 1d-4 , > > nstep = 20000 , > > tstress = .false. , > > tprnfor = .false. , > > dt=20.67, > > isave = 100, > > iprint = 10, > > ndr = 51, > > ndw = 51, > > restart_mode = 'from_scratch', > > verbosity = 'low' , > > / > > > > &SYSTEM > > ibrav=14, > > celldm(1)=36.1187133640d0, celldm(2)=0.6119121863d0, > > celldm(3)=1.3079965678d0, > > celldm(4)=0.0000000000d0, celldm(5)=0.0000000000d0, > > celldm(6)=0.0000000000d0, > > nat=63, > > ntyp=2, > > ecutwfc=50, > > ecutrho=400, > > input_dft='PBE', > > vdw_corr = 'DFT-D3' , > > nr1b = 16 , > > nr2b = 16 , > > nr3b = 16 , > > nosym = .true. , > > / > > &ELECTRONS > > emass = 400 > > emass_cutoff = 2.50, > > electron_dynamics='damp', > > electron_damping=0.2, > > / > > &IONS > > ion_dynamics='none', > > ion_radius(1)=1.0, ion_radius(2)=1.0, > > / > > > > ATOMIC_SPECIES > > C 12.010700d0 C_pbe_v1.2.uspp.F.UPF > > P 30.973800d0 P.pbe-n-rrkjus_psl.1.0.0.UPF > > > > ATOMIC_POSITIONS {crystal} > > P 0.207062953 0.994563394 0.532135751 > > P 0.042823633 0.994796583 0.465770116 > > C 0.157559602 0.119473623 0.509211511 > > C 0.092142096 0.120398444 0.486938482 > > P 0.453113260 0.016237452 0.533698293 > > P 0.289980002 0.986689982 0.464529400 > > C 0.399646081 0.133053286 0.505994952 > > C 0.335858066 0.117232823 0.482213070 > > P 0.704320783 0.007706925 0.532982064 > > P 0.538824580 0.008408401 0.468045855 > > C 0.654037234 0.132822314 0.511474768 > > C 0.587848371 0.135094109 0.489114957 > > P 0.956731588 -0.000006745 0.532145072 > > P 0.791554157 0.002228032 0.466394516 > > C 0.907495292 0.125510515 0.509696521 > > C 0.841931621 0.126642797 0.487430517 > > P 0.208266817 0.243782922 0.529541853 > > P 0.043965854 0.246589308 0.464392818 > > C 0.158728245 0.369838186 0.509463992 > > C 0.093217169 0.370873210 0.486709312 > > P 0.424177849 0.286343852 0.516852430 > > P 0.290089532 0.244400471 0.459582516 > > C 0.349540011 0.348792825 0.487513040 > > P 0.705574516 0.255089554 0.532107492 > > P 0.542012221 0.260506971 0.464249905 > > C 0.656129286 0.380833823 0.512136142 > > C 0.590214180 0.381152001 0.490082742 > > P 0.957108151 0.250073183 0.531244245 > > P 0.792998637 0.251922321 0.464998669 > > C 0.907321789 0.375462368 0.510050868 > > C 0.841746979 0.376334296 0.487596817 > > P 0.208402877 0.492352243 0.532960869 > > P 0.043963546 0.496372026 0.465432581 > > C 0.160144417 0.618157610 0.509696507 > > C 0.094342113 0.619600026 0.487659242 > > P 0.471073678 0.513328655 0.548894023 > > P 0.309129724 0.486227608 0.474070256 > > C 0.414925399 0.629235003 0.523346545 > > C 0.350961159 0.616373438 0.499640968 > > P 0.705395802 0.505478539 0.534378721 > > P 0.537192856 0.506995560 0.474222102 > > C 0.656825419 0.631333460 0.511436510 > > C 0.590845794 0.632466501 0.490389008 > > P 0.956482750 0.499986748 0.532254831 > > P 0.791270143 0.501641183 0.466922839 > > C 0.906923580 0.625196225 0.510129362 > > C 0.841214140 0.626345388 0.488309739 > > P 0.207667541 0.743674910 0.533472131 > > P 0.043998636 0.744658734 0.465730512 > > C 0.158052412 0.868776604 0.510578825 > > C 0.092761413 0.869723388 0.488195850 > > P 0.461194613 0.761061943 0.539728957 > > P 0.299530254 0.737206731 0.471960596 > > C 0.407654987 0.881987587 0.515312903 > > C 0.343486860 0.870097791 0.492007540 > > P 0.706175574 0.757137135 0.532107627 > > P 0.539960743 0.756974729 0.469099032 > > C 0.655720285 0.882343139 0.510585276 > > C 0.589586421 0.883272199 0.489712695 > > P 0.956945276 0.749651294 0.531828394 > > P 0.791991567 0.752132650 0.465926241 > > C 0.907222485 0.875386768 0.509910655 > > C 0.841486983 0.876756958 0.488249976 > > > > K_POINTS {gamma} > > > > Thanks. > > > > LIANG Xiongyi > > City University of Hong Kong > > > > GIUSEPPE MATTIOLI > CNR - ISTITUTO DI STRUTTURA DELLA MATERIA > Via Salaria Km 29,300 - C.P. 10 > I-00015 - Monterotondo Scalo (RM) > Mob (*preferred*) +39 373 7305625 > Tel + 39 06 90672342 - Fax +39 06 90672316 > E-mail: <[email protected]> > > _______________________________________________ > users mailing list > [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users > _______________________________________________ > users mailing list > [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users -- Paolo Giannozzi, Dip. 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