<div dir="auto">Dear Dr. Giuseppe<div dir="auto"><br></div><div dir="auto">Thank you very much for the detailed information.</div><div dir="auto"><br></div><div dir="auto">Yes, I removed 4 H-atoms (two hydrogen molecules) not 2 (-1H2). </div><div dir="auto">I am trying for liberation of different H-atoms and with this particular configurations the structure didn't converge.</div><div dir="auto"><br></div><div dir="auto">I will check it out with your suggestions.</div><div dir="auto"><br></div><div dir="auto">Thank you very much</div><div dir="auto">Bhamu</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jan 6, 2021, 03:18 Giuseppe Mattioli <<a href="mailto:giuseppe.mattioli@ism.cnr.it">giuseppe.mattioli@ism.cnr.it</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Dear K C Bhamu<br>
When you simulate molecules having a large amount of rotational <br>
degrees of freedom, I recommend to use first a tight-binding or <br>
empirical tool to explore configurations, to avoid high-energy <br>
structures. The following one is excellent, very easy to use and very <br>
fast to run.<br>
<br>
<a href="https://xtb-docs.readthedocs.io/en/latest/contents.html" rel="noreferrer noreferrer" target="_blank">https://xtb-docs.readthedocs.io/en/latest/contents.html</a><br>
<br>
This said, your starting configuration was trapped in an unfortunate <br>
structure where two sp2 C atoms (numbers 33 and 35) were twisted <br>
instead of being planar. You probably removed two H atoms from sp3 <br>
atoms without relaxing them. The following structure, simply optimized <br>
with a force-field, should not give problems (but I have not run the <br>
calculation...).<br>
<br>
45<br>
Energy: 52.7144978<br>
H 8.48608 10.45663 13.88529<br>
C 10.12285 10.35161 10.80715<br>
H 9.75081 9.36965 10.43974<br>
C 11.49997 10.08512 11.39597<br>
H 12.30756 9.85722 10.70499<br>
C 11.75878 10.11652 12.72470<br>
C 10.64679 10.32692 13.74405<br>
H 10.74317 9.58583 14.56637<br>
H 10.73789 11.33550 14.19281<br>
C 9.24848 10.13193 13.14479<br>
H 9.07291 9.05796 12.91129<br>
C 9.14194 10.92818 11.85742<br>
H 8.10293 10.88215 11.46867<br>
H 9.38712 11.98966 12.08748<br>
C 8.94637 11.52201 8.84268<br>
C 10.25893 11.30287 9.59702<br>
H 9.13189 12.17491 7.96386<br>
H 8.19218 12.02297 9.48301<br>
H 8.54193 10.55155 8.48460<br>
H 10.65844 12.28636 9.92936<br>
H 10.98302 10.86213 8.87653<br>
C 13.17440 9.88279 13.22285<br>
H 13.11888 9.04537 13.95078<br>
H 13.83707 9.54798 12.39520<br>
C 15.69736 11.92481 15.44478<br>
H 16.74498 11.70891 15.74860<br>
H 15.07047 11.97162 16.36387<br>
C 15.58617 13.25420 14.70482<br>
H 16.14427 13.14997 13.74597<br>
C 14.09237 13.52300 14.41126<br>
H 14.03472 14.35009 13.67327<br>
H 13.54419 13.83190 15.32752<br>
C 13.36446 12.32498 13.84523<br>
C 13.87547 11.06693 13.87464<br>
C 15.21374 10.78810 14.53332<br>
H 15.14294 9.87981 15.16991<br>
H 15.94984 10.58575 13.72543<br>
C 16.23591 15.73576 14.79615<br>
C 16.23058 14.39236 15.52642<br>
H 16.75074 16.49369 15.42343<br>
H 15.20340 16.09456 14.60831<br>
H 16.77780 15.64679 13.83071<br>
H 15.70219 14.50766 16.49821<br>
H 17.28870 14.12285 15.73764<br>
H 12.40535 12.52093 13.38556<br>
<br>
Finally,<br>
<br>
> occupations='smearing',<br>
> smearing='mv',<br>
> degauss=0.005d0,<br>
<br>
This is just a fine way for me to calculate a bunch of unoccupied <br>
molecular orbitals, but there is no need to use 'mv', which is for <br>
metals and less stable than 'gaussian', suitable for an "insulator" <br>
such as your molecule. I would use instead<br>
<br>
occupations='smearing', smearing='gaussian', degauss=0.01,<br>
<br>
HTH<br>
Giuseppe<br>
<br>
<br>
Quoting "Dr. K. C. Bhamu" <<a href="mailto:kcbhamu85@gmail.com" target="_blank" rel="noreferrer">kcbhamu85@gmail.com</a>>:<br>
<br>
> Dear QE Users<br>
> I wish you all a very happy new year 2021!<br>
><br>
> I am running a molecule with QE_6.6 but facing a convergence problem.<br>
> I tried with and without 'local-TF' and both the options are not working.<br>
><br>
> Could someone please have a look and suggest to me any solution?<br>
><br>
><br>
> &CONTROL<br>
> calculation = 'relax'<br>
> restart_mode = 'from_scratch'<br>
> outdir = './tmp'<br>
> pseudo_dir = '/home/kcbhamu/PPs'<br>
> prefix = 'pwscf'<br>
> ! disk_io = 'none'<br>
> verbosity = 'default'<br>
> etot_conv_thr = 0.0001<br>
> forc_conv_thr = 0.001<br>
> nstep = 400<br>
> tstress = .true.<br>
> tprnfor = .true.<br>
> /<br>
><br>
> &SYSTEM<br>
> ibrav=1,<br>
> celldm(1)=47.2431531141d0,<br>
> nat=45,<br>
> ntyp=2,<br>
> ecutwfc=65,<br>
> ecutrho=650,<br>
> occupations='smearing',<br>
> smearing='mv',<br>
> degauss=0.005d0,<br>
> vdw_corr = 'DFT-D3'<br>
> assume_isolated='mt'<br>
> /<br>
><br>
> &ELECTRONS<br>
> electron_maxstep=999<br>
> conv_thr=1d-06,<br>
> mixing_beta=0.2,<br>
> mixing_mode='local-TF'<br>
><br>
> /<br>
> &IONS<br>
> ion_dynamics = 'bfgs'<br>
> /<br>
><br>
> ATOMIC_SPECIES<br>
> C 12.0107000000 C.pbe-n-rrkjus_psl.1.0.0.UPF<br>
> H 1.0079000000 H.pbe-rrkjus_psl.1.0.0.UPF<br>
><br>
><br>
> ATOMIC_POSITIONS {crystal}<br>
> H 0.3386670148d0 0.4101931225d0 0.5567254731d0<br>
> C 0.4036222773d0 0.4149138472d0 0.4333448459d0<br>
> H 0.3896346255d0 0.3765041141d0 0.4161167921d0<br>
> C 0.4581434036d0 0.4058061800d0 0.4574431361d0<br>
> H 0.4912475090d0 0.4017946150d0 0.4290030859d0<br>
> C 0.4691277774d0 0.4031817060d0 0.5099401207d0<br>
> C 0.4253264110d0 0.4071145213d0 0.5513729998d0<br>
> H 0.4327529164d0 0.3774401630d0 0.5831675023d0<br>
> H 0.4276381009d0 0.4464313224d0 0.5714430496d0<br>
> C 0.3695729050d0 0.3993621172d0 0.5273547231d0<br>
> H 0.3636345597d0 0.3567170026d0 0.5178739313d0<br>
> C 0.3632663685d0 0.4323236400d0 0.4762330101d0<br>
> H 0.3222111650d0 0.4290965819d0 0.4608472936d0<br>
> H 0.3700270318d0 0.4749720278d0 0.4855397879d0<br>
> C 0.3550607872d0 0.4623307485d0 0.3556503474d0<br>
> C 0.4072533598d0 0.4549686753d0 0.3866434814d0<br>
> H 0.3606425820d0 0.4892876373d0 0.3214193048d0<br>
> H 0.3233410756d0 0.4794322728d0 0.3807732671d0<br>
> H 0.3403880199d0 0.4238800875d0 0.3400782741d0<br>
> H 0.4209431037d0 0.4937648655d0 0.4025522295d0<br>
> H 0.4387880407d0 0.4413449118d0 0.3590270889d0<br>
> C 0.5253811195d0 0.3963553146d0 0.5303629030d0<br>
> H 0.5275121376d0 0.3597814346d0 0.5550954410d0<br>
> H 0.5527498198d0 0.3902494747d0 0.4963382387d0<br>
> C 0.6241002137d0 0.4781543529d0 0.6196978697d0<br>
> H 0.6647510385d0 0.4689076884d0 0.6339462788d0<br>
> H 0.5991190333d0 0.4830564471d0 0.6558173241d0<br>
> C 0.6245138950d0 0.5312336801d0 0.5887880064d0<br>
> H 0.6519223460d0 0.5264394769d0 0.5543229817d0<br>
> C 0.5684449407d0 0.5426728657d0 0.5664333374d0<br>
> H 0.5687315910d0 0.5794127480d0 0.5422455469d0<br>
> H 0.5411292134d0 0.5502889434d0 0.6003493599d0<br>
> C 0.5467291274d0 0.4961698023d0 0.5329872592d0<br>
> H 0.5063039439d0 0.5054115901d0 0.5182523433d0<br>
> C 0.5462494021d0 0.4434602904d0 0.5642948220d0<br>
> C 0.6023141698d0 0.4317080266d0 0.5862549648d0<br>
> H 0.6016470576d0 0.3946830496d0 0.6101287345d0<br>
> H 0.6295099445d0 0.4241153738d0 0.5522682608d0<br>
> C 0.6550325759d0 0.6297412310d0 0.5941577656d0<br>
> C 0.6461033707d0 0.5769127641d0 0.6236837684d0<br>
> H 0.6727321964d0 0.6599556430d0 0.6206848621d0<br>
> H 0.6175101186d0 0.6464185973d0 0.5785534114d0<br>
> H 0.6823409744d0 0.6243625417d0 0.5600843513d0<br>
> H 0.6183422352d0 0.5832463756d0 0.6574159578d0<br>
> H 0.6841825362d0 0.5638719462d0 0.6416905666d0<br>
><br>
> K_POINTS (gamma)<br>
><br>
><br>
><br>
> Thank you very much<br>
> K C Bhamu<br>
> University of Ulsan<br>
> ROK<br>
<br>
<br>
<br>
GIUSEPPE MATTIOLI<br>
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA<br>
Via Salaria Km 29,300 - C.P. 10<br>
I-00015 - Monterotondo Scalo (RM)<br>
Mob (*preferred*) +39 373 7305625<br>
Tel + 39 06 90672342 - Fax +39 06 90672316<br>
E-mail: <<a href="mailto:giuseppe.mattioli@ism.cnr.it" target="_blank" rel="noreferrer">giuseppe.mattioli@ism.cnr.it</a>><br>
<br>
_______________________________________________<br>
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</blockquote></div>