<div dir="ltr">Dear Giuseppe,<br><br>Thank you for your insightful reply and valuable suggestions. I am trying to simulate the ring opening of boron oxide-bounded epoxide through the nucleophilic attack of Br- anion.<br><br>I will implement your recommendations, including trying alternative pseudo potentials and exploring additional factors you highlighted. As a newcomer to quantum espresso, I am eager to learn and experiment with different approaches to enhance my understanding.<br><br>I noticed that the paper I've been following on Boron oxide used the pbesol pseudopotential, but they focused on neutral molecules. Given your suggestions, I plan to explore variations using different pseudo potentials and different ecut and erho values to assess their impact on the simulation.<br><br>Once again, thank you for your support, and I look forward to further refining my simulations with your insights.<br><br>Best regards,<br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Nikunj kumar<div>Research Scholar</div><div>Chemistry Department</div><div>IIT Roorkee</div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Feb 3, 2024 at 9:43 PM 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:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
Dear Nikunj Kumar<br>
You are trying to attach an excess electron to a Br atom placed in the <br>
vacuum above a boron oxide slab in contact with an organic molecule. <br>
Br is not screened by some dielectric environment like water or a <br>
surrounding solid structure. When treated at the GGA level of theory, <br>
excess electrons in anions in vacuum are unbound, i.e., their energy <br>
is above the vacuum level; it is a theoretical problem, not a <br>
technical problem. I don't know your system, maybe your excess <br>
electron is delocalized across the oxide conduction band, maybe not. <br>
It is unpredictable but if you are trying to model Br(-) this is not <br>
the correct way. Moreover, you are using a huge and likely useless <br>
basis set for paw pseudopotentials, with ecutwfc=250 Ry and <br>
ecutrho=1000 Ry. occupations='fixed' and smearing='gaussian' are also <br>
incompatible. All of these issues can lead to scf instabilites. As I <br>
don't know what you expect to simulate, I cannot say more than this.<br>
HTH<br>
Giuseppe<br>
<br>
<br>
Quoting NIKUNJ KUMAR <<a href="mailto:n_kumar2@cy.iitr.ac.in" target="_blank">n_kumar2@cy.iitr.ac.in</a>>:<br>
<br>
> Hello everyone,<br>
><br>
> I hope this message finds you well. I am currently facing a challenge in a<br>
> 'relax' type calculation, specifically when introducing a Br anion into my<br>
> system with a total charge of -1. The issue arises as the calculation stops<br>
> after just 2 SCF iterations, accompanied by the following error message:<br>
> Error in routine rdiaghg (640):<br>
> problems computing cholesky<br>
><br>
><br>
> Interestingly, the calculation was running smoothly before the introduction<br>
> of Br into the system. For context, I am utilizing the PBEsol paw type pp<br>
> from the pseudo dojo database, and the input file is written below for your<br>
> reference.<br>
><br>
><br>
> &CONTROL<br>
> calculation = "relax"<br>
> forc_conv_thr = 1.00000e-06<br>
> max_seconds = 1.72800e+05<br>
> nstep = 500<br>
> disk_io = 'none'<br>
> pseudo_dir = "./"<br>
> outdir ="./temp"<br>
> /<br>
><br>
> &SYSTEM<br>
> a = 9.43592e+00<br>
> b = 1.30441e+01<br>
> c = 4.02484e+01<br>
> cosab = -2.30389e-01<br>
> degauss = 1.00000e-02<br>
> ecutrho = 1.00000e+03<br>
> ecutwfc = 2.50000e+02<br>
> ibrav = 12<br>
> nat = 146<br>
> ntyp = 5<br>
> tot_charge =-1<br>
> occupations = "fixed"<br>
> smearing = "gaussian"<br>
> /<br>
><br>
> &ELECTRONS<br>
> conv_thr = 1.00000e-08<br>
> electron_maxstep = 300<br>
> mixing_beta = 7.00000e-01<br>
> startingpot = "atomic"<br>
> startingwfc = "atomic+random"<br>
> /<br>
><br>
> &IONS<br>
> ion_dynamics = "bfgs"<br>
> /<br>
><br>
><br>
> K_POINTS {gamma}<br>
><br>
> ATOMIC_SPECIES<br>
> B 10.81100 B.upf<br>
> O 15.99940 O.upf<br>
> C 12.01070 C.upf<br>
> H 1.00794 H.upf<br>
> Br 79.90400 Br.upf<br>
><br>
> ATOMIC_POSITIONS {angstrom}<br>
> O 3.754834000 3.515156000 17.208519000<br>
> O 0.034436000 1.520892000 16.066045000<br>
> O 7.160635000 1.044462000 16.356461000<br>
> O 3.357263000 1.185774000 16.842398000<br>
> O 0.519323000 1.958041000 18.342909000<br>
> O 1.455747000 3.299351000 16.553832000<br>
> O 7.803889000 3.883560000 17.375196000<br>
> O 5.437775000 1.991195000 17.699831000<br>
> B 2.514843000 4.050588000 16.913192000<br>
> B 8.488318000 0.701095000 16.527892000<br>
> B 6.473887000 1.125469000 17.544128000<br>
> B 4.175154000 2.200028000 17.242716000<br>
> B 0.715437000 2.263118000 17.003418000<br>
> O 5.720922000 1.823850000 20.878023000<br>
> O 1.438122000 3.840152000 19.415577000<br>
> O 7.744065000 3.462649000 19.686233000<br>
> O 7.036262000 0.570535000 18.688600000<br>
> O 4.307513000 3.723392000 20.530664000<br>
> O 2.769498000 0.048093000 21.722688000<br>
> O 3.480766000 1.602073000 20.023812000<br>
> O 0.469955000 2.038326000 20.704597000<br>
> O 7.410831000 0.298249000 21.385070000<br>
> B 4.489103000 2.357617000 20.570624000<br>
> B 0.775613000 2.638077000 19.505559000<br>
> B 7.418619000 3.693276000 21.006039000<br>
> B 7.183884000 4.035133000 18.588513000<br>
> B 6.170982000 0.521811000 20.838073000<br>
> B 2.956880000 0.400145000 20.402662000<br>
> O 4.699394000 12.674672000 24.573063000<br>
> O 3.697946000 2.010965000 22.720733000<br>
> O 0.462997000 1.946967000 23.066403000<br>
> O 8.235206000 3.218267000 21.993446000<br>
> O 6.303865000 1.885557000 24.211038000<br>
> O 3.369105000 2.381461000 25.051568000<br>
> O 4.484631000 4.000335000 23.708815000<br>
> O 2.522918000 0.399802000 24.032915000<br>
> O 8.458849000 2.724160000 24.854635000<br>
> B 6.519079000 0.521498000 24.171811000<br>
> B 3.012943000 0.811264000 22.820437000<br>
> B 0.150363000 2.131320000 24.405538000<br>
> B -0.070477000 2.439831000 21.903483000<br>
> B 7.173750000 2.920360000 24.501766000<br>
> B 3.950419000 2.759753000 23.864979000<br>
> O 2.753087000 7.746220000 17.208561000<br>
> O -0.967323000 5.751970000 16.066081000<br>
> O 6.158876000 5.275511000 16.356477000<br>
> O 2.355519000 5.416843000 16.842391000<br>
> O -0.482390000 6.189090000 18.342952000<br>
> O 0.454016000 7.530423000 16.553849000<br>
> O 6.802161000 8.114608000 17.375205000<br>
> O 4.436024000 6.222260000 17.699837000<br>
> B 1.513087000 8.281653000 16.913251000<br>
> B 7.486569000 4.932166000 16.527915000<br>
> B 5.472143000 5.356533000 17.544135000<br>
> B 3.173410000 6.431096000 17.242725000<br>
> B -0.286307000 6.494181000 17.003439000<br>
> O 4.719193000 6.054910000 20.878019000<br>
> O 0.436375000 8.071207000 19.415579000<br>
> O 6.742321000 7.693691000 19.686251000<br>
> O 6.034527000 4.801615000 18.688628000<br>
> O 3.305773000 7.954452000 20.530671000<br>
> O 1.767778000 4.279151000 21.722684000<br>
> O 2.479032000 5.833133000 20.023815000<br>
> O -0.531763000 6.269387000 20.704630000<br>
> O 6.409076000 4.529299000 21.385089000<br>
> B 3.487370000 6.588693000 20.570626000<br>
> B -0.226116000 6.869125000 19.505577000<br>
> B 6.416861000 7.924320000 21.006056000<br>
> B 6.182148000 8.266183000 18.588552000<br>
> B 5.169244000 4.752884000 20.838058000<br>
> B 1.955162000 4.631204000 20.402686000<br>
> O 6.702867000 4.212530000 24.573064000<br>
> O 2.696219000 6.242038000 22.720750000<br>
> O -0.538742000 6.178032000 23.066436000<br>
> O 7.233459000 7.449290000 21.993473000<br>
> O 5.302127000 6.116622000 24.211072000<br>
> O 2.367344000 6.612542000 25.051580000<br>
> O 3.482901000 8.231408000 23.708851000<br>
> O 1.521183000 4.630874000 24.032930000<br>
> O 7.457120000 6.955218000 24.854674000<br>
> B 5.517340000 4.752563000 24.171827000<br>
> B 2.011219000 5.042342000 22.820454000<br>
> B -0.851385000 6.362375000 24.405579000<br>
> B -1.072217000 6.670889000 21.903521000<br>
> B 6.172007000 7.151421000 24.501813000<br>
> B 2.948682000 6.990824000 23.864988000<br>
> O 1.751358000 11.977290000 17.208560000<br>
> O -1.969011000 9.982977000 16.066085000<br>
> O 5.157183000 9.506595000 16.356501000<br>
> O 1.353766000 9.647903000 16.842472000<br>
> O -1.484108000 10.420131000 18.342941000<br>
> O -0.547722000 11.761459000 16.553848000<br>
> O 5.800420000 12.345689000 17.375160000<br>
> O 3.434303000 10.453319000 17.699866000<br>
> B 0.511368000 12.512710000 16.913221000<br>
> B 6.484857000 9.163207000 16.527937000<br>
> B 4.470421000 9.587610000 17.544172000<br>
> B 2.171680000 10.662166000 17.242767000<br>
> B -1.288002000 10.725220000 17.003453000<br>
> O 3.717455000 10.285980000 20.878022000<br>
> O -0.565377000 12.302292000 19.415566000<br>
> O 5.740577000 11.924763000 19.686206000<br>
> O 5.032803000 9.032678000 18.688644000<br>
> O 2.304042000 12.185525000 20.530674000<br>
> O 0.766025000 8.510198000 21.722689000<br>
> O 1.477279000 10.064188000 20.023840000<br>
> O -1.533488000 10.500450000 20.704628000<br>
> O 5.407345000 8.760358000 21.385107000<br>
> B 2.485638000 10.819745000 20.570636000<br>
> B -1.227842000 11.100195000 19.505580000<br>
> B 5.415136000 12.155400000 21.006013000<br>
> B 5.180404000 12.497244000 18.588499000<br>
> B 4.167507000 8.983948000 20.838079000<br>
> B 0.953421000 8.862268000 20.402697000<br>
> O 5.701119000 8.443598000 24.573135000<br>
> O 1.694495000 10.473076000 22.720741000<br>
> O -1.540481000 10.409130000 23.066430000<br>
> O 6.231728000 11.680379000 21.993433000<br>
> O 4.300402000 10.347699000 24.211071000<br>
> O 1.365633000 10.843622000 25.051563000<br>
> O 2.481179000 12.462473000 23.708784000<br>
> O 0.519432000 8.861950000 24.032934000<br>
> O 6.455369000 11.186313000 24.854672000<br>
> B 4.515612000 8.983625000 24.171867000<br>
> B 1.009477000 9.273392000 22.820457000<br>
> B -1.853101000 10.593479000 24.405573000<br>
> B -2.073947000 10.901966000 21.903504000<br>
> B 5.170284000 11.382499000 24.501782000<br>
> B 1.946953000 11.221874000 23.864965000<br>
> O 1.091093000 1.770835000 25.342768000<br>
> B 2.336349000 1.479483000 24.879956000<br>
> O 0.089354000 6.001874000 25.342804000<br>
> B 1.334608000 5.710544000 24.879962000<br>
> O -0.912369000 10.232995000 25.342798000<br>
> B 0.332877000 9.941635000 24.879959000<br>
> O 1.169790100 6.398079898 26.506082736<br>
> C 1.709966097 6.138246887 27.857097216<br>
> H 2.707261284 5.674065569 27.859423989<br>
> H 0.950878912 5.727882556 28.541990554<br>
> C 1.592297489 7.517135394 27.386071061<br>
> H 2.536403144 7.989815029 27.065205411<br>
> C 0.502211237 8.436139117 27.843173529<br>
> H 0.277193205 9.207901622 27.080667387<br>
> H 0.866246418 8.935911811 28.764585931<br>
> H -0.425494252 7.878719382 28.079324886<br>
> Br 3.392772496 8.082664561 30.255606626<br>
><br>
> Thank you in advance for your assistance!<br>
> Nikunj kumar<br>
> Research Scholar<br>
> Chemistry Department<br>
> IIT Roorkee<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">giuseppe.mattioli@ism.cnr.it</a>><br>
<br>
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</blockquote></div>