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Hello Ashley cooper. Based on my limited knowledge I can tell you that, HSE06 is not at all for vc-relax calculations. You should relax your system with some GGA functional like PBE or PBEsol. Once you have relaxed structure then you run scf calculation while using hybrid dft. It will still take long time. <br><br><br><div class="yahoo-signature"><a style="font-size:12px" href="https://mail.onelink.me/107872968?pid=nativeplacement&c=Global_Acquisition_YMktg_315_Internal_EmailSignature&af_sub1=Acquisition&af_sub2=Global_YMktg&af_sub3=&af_sub4=100000604&af_sub5=EmailSignature__Static_&af_ios_store_cpp=9d3a686e-218d-4849-8298-b480188dc8ac&af_android_url=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dcom.yahoo.mobile.client.android.mail%26listing%3Demail_signature">Sent from Yahoo Mail for iPhone</a><br></div><br><p class="yahoo-quoted-begin" style="font-size: 15px; color: rgb(132, 115, 255); padding-top: 15px; margin-top: 0px;">On Monday, August 25, 2025, 5:11 PM, Barsha Pal <barsha.pal@aus.ac.in> wrote:</p><blockquote class="iosymail"><div id="yiv6029481219"><div dir="ltr">I am trying to optimize an hexagonal unit cell with HSE06 functional. But the optimization is running for 12 days and still stuck at bfgs step 2, with scf step count 34, the optimization taking a long time. The input specifications are:<div><br><div>&CONTROL<br> calculation = "vc-relax"<br> restart_mode = "from_scratch" <br> forc_conv_thr = 1.00000e-04<br> etot_conv_thr = 1.00000e-05<br> outdir = "/"<br> prefix = "hse_opt"<br> pseudo_dir = "/"<br> verbosity = "high"<br>/<br><br>&SYSTEM<br> celldm(1) = 15.36942147<br> degauss = 1.00000e-02<br> ecutrho = 560 <br> ecutwfc = 140<br> ibrav = 0<br> nat = 12<br> ntyp = 3<br> occupations = "smearing"<br> smearing = "gaussian"<br> input_dft = "hse"<br> exx_fraction = 0.25 <br> screening_parameter = 0.106 <br> exxdiv_treatment = "gygi-baldereschi" <br> x_gamma_extrapolation = .true. <br> nqx1 = 2, <br> nqx2 = 2, <br> nqx3 = 1,<br> assume_isolated = "2D" <br>/<br><br>&ELECTRONS<br> conv_thr = 1.00000e-08<br> electron_maxstep = 300<br> mixing_beta = 7.00000e-01<br> diagonalization ='david'<br> mixing_mode = 'plain'<br>/<br><br>&IONS<br> ion_dynamics = "bfgs"<br>/<br><br>&CELL<br> cell_dofree = "2Dxy"<br> cell_dynamics = "bfgs"<br> press = 0.00000e+00<br> press_conv_thr = 0.5<br>/<br><br>K_POINTS {automatic}<br> 12 12 1 0 0 0<br><br>ATOMIC_SPECIES<br>A 1 A.pbe-mt_fhi.UPF<br>B 1 B.pbe-mt_fhi.UPF<br>C 1 C.pbe-mt_fhi.UPF<br></div><div><br></div><div><br></div><div><br></div><div><br></div><div>Previously I tried to run with q points 3 3 1 and the optimization was running at bfgs step 2 for 1 month,</div><div><br></div><div>How can I use the functional and reduce the computational time? Please let me know. </div><div><br></div><div><br></div><div><br></div><div><br></div><div>Ashley Cooper</div><div>Phd</div></div></div>
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