Okay! I am looking at them.<div><br /></div><div>Thank you!</div><div>Asif<br /><br /></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Monday, 20 July 2026 at 07:55:48 UTC-4 Johann Pototschnig wrote:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div>There is the option to remain in the same space group:</div><div>KEEP_SPACE_GROUP</div><div><a href="https://manual.cp2k.org/trunk/CP2K_INPUT/MOTION/GEO_OPT.html#CP2K_INPUT.MOTION.GEO_OPT.KEEP_SPACE_GROUP" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://manual.cp2k.org/trunk/CP2K_INPUT/MOTION/GEO_OPT.html%23CP2K_INPUT.MOTION.GEO_OPT.KEEP_SPACE_GROUP&source=gmail&ust=1784701782563000&usg=AOvVaw250Q1Ox1wOvIrp9quKbT2J">https://manual.cp2k.org/trunk/CP2K_INPUT/MOTION/GEO_OPT.html#CP2K_INPUT.MOTION.GEO_OPT.KEEP_SPACE_GROUP</a></div><div>but they require a C2v space group to start with. </div><div><br></div><div>There are additional constrains possible, but for a 72 atom system, they are not useful:</div><div><a href="https://manual.cp2k.org/cp2k-2024_2-branch/CP2K_INPUT/MOTION/CONSTRAINT.html" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://manual.cp2k.org/cp2k-2024_2-branch/CP2K_INPUT/MOTION/CONSTRAINT.html&source=gmail&ust=1784701782564000&usg=AOvVaw01XsdrjYxrOlMiNmpXoypV">https://manual.cp2k.org/cp2k-2024_2-branch/CP2K_INPUT/MOTION/CONSTRAINT.html</a></div><div><br></div><div><br></div><div><br></div><div><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Saturday, July 18, 2026 at 3:27:10 PM UTC+2 Asif Billah wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi CP2K community,<br><br>I am studying Be substituting Ga in wurtzite GaN using CP2K/GPW with HSE + ADMM. <div><br></div><div>Based on previous resources, it is possible to obtain three different configurations for Be in GaN.</div><div>C3v: one long axial Be-N bond</div><div>pseudo-C3v: one long basal Be-N bond</div><div>C2v: distortion of the two adjacent acceptor-nitrogen bonds, not a single bond is significantly long</div><div><br></div><div>I am trying to locate the shallow C2v like acceptor configuration, but so far my relaxations either converge to the deep C3v or pseudo-C3v polaronic states.<div><div><br></div><div>I have already found stable/converged neutral C3v and pseudo-C3v branches. In the 72-atom cell at α = 0.335, the pseudo-C3v branch is with one long basal Be-N bond around 2.56 Å. The C3v branch has one long axial Be-N bond around 2.59 Å. These two states can be obtained easily where the initial structure will be by distorting the Be atom such that there will be a long basal or axial bond. </div><div><br></div><div>The shallow C2v state of Be_Ga acceptor results from the distortion of the two adjacent acceptor-nitrogen bonds, having the C2v symmetry of the atomic structure. The hole in this case is anisotropically delocalized in the (0001) wurtzite plane of GaN.</div><div><br></div><div>Hence, for the C2v search, I am giving an initial structure by distorting the Be atom along a bisector direction involving the axial N neighbor and one basal N neighbor. However, it starts to collapse to the C3v/pseudo-C3v state.<br><br>My question is: does anyone have advice on how to better initialize or constrain the search for the shallow C2v acceptor state in CP2K? Is it possible to obtain C2v state? In particular, I would appreciate suggestions on:<br><br>1. Better initial distortion pattern for C2v in wurtzite GaN<br>2. Better spin/localization initialization for the hole<br>3. Any CP2K-specific GEO_OPT/HSE/ADMM settings that help avoid collapse into C3v or pseudo-C3v<br><br>Any guidance would be very helpful. Thank you!</div></div></div><div><br></div><div>Ps:</div><div>My current setup is:<br><br>System: Be_Ga in wurtzite GaN<br>Cell sizes tested: 72 atoms, moving to 108 and 300 atoms<br>Run type: GEO_OPT, fixed cell<br>Functional: HSE-style screened hybrid<br>alpha = 0.335<br>omega = 0.1058354422 bohr^-1 # approximately 0.2 Å^-1<br>MGRID cutoff = 600 Ry<br>REL_CUTOFF = 60 Ry<br>SCF: OT-CG, FULL_ALL preconditioner<br>q = 0: UKS TRUE, MULTIPLICITY 2<br>q = -1: UKS FALSE<br>HFX: four-center HFX + ADMM<br><br>Basis/pseudopotential setup:<br><br>Ga: DZVP-MOLOPT-PBE0-GTH-q13 + admm-dz-q13, GTH-PBE0-q13<br>N : DZVP-MOLOPT-PBE0-GTH-q5 + admm-dz-q5, GTH-PBE0-q5<br>Be: DZVP-MOLOPT-PBE0-GTH-q4 + admm-dz-q4, GTH-PBE0-q4<br></div></blockquote></div></blockquote></div>
<p></p>
-- <br />
You received this message because you are subscribed to the Google Groups "cp2k" group.<br />
To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>.<br />
To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/e3005638-8ca8-4276-9046-ad8621ae39a0n%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/e3005638-8ca8-4276-9046-ad8621ae39a0n%40googlegroups.com</a>.<br />