Thanks for the reply. I do restart from GGA; I am also using a range separated functional as the hf_admm_utils.F module actually takes the coulomb and longrange scales and uses them to activate PBE_HOLE_TRUNC_LR and XWPBE sections. <div><br></div><div>On the point of the short cutoff radius: there is actually a little uncertainty in the ideal cutoff radius. In one sense, we would like to have the truncated PBE0 converged w.r.t full 1/r, but there is some literature evidence that the PBE0 form should be treated as a short-range interaction, and the cutoff should be short. Since the short and long range terms have different ideal mixing fractions, if we extend PBE0 cutoff out too far (like 6-8Å), then while we are reproducing exact 1/r pretty well, we are applying short-range mixing fraction beyond where we should. </div><div><br></div><div>Anyway, that's just an aside if you're interested. Thanks for the assistance.</div><div><br></div><div>-Nick<br><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Monday, November 2, 2020 at 2:29:40 AM UTC-8 Augustin Bussy 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;"><font face="Default Sans Serif,Verdana,Arial,Helvetica,sans-serif" size="2"><div>Dear Nicholas,</div><div><br></div><div>your XC input looks fine to me, but I have a few remarks. The cutoffs of the truncated Coulomb potential and the long range erf functions are very short. We typically use cutoffs that are around 6 Angstrom, which ensures that results are close enough to a calculation with standard Coulomb potential. Unless you are restarting your calculation from a well converged GGA level calculation, I would refrain from using the SCREEN_ON_INITIAL_P keyword, as the ATOMIC_GUESS starting point might not be good enough for porper screening. Finally, if you are using a range spearated HF potentials, you might want to combine it with a range separated DFT exchange functional as well.</div><div><br></div><div>I assume you set up the ADMM section properly and made a sensible choice of primary and auxiliary basis sets. Without your full input file however, this is impossible to say whether there is an issue there.<br></div><div><br></div><div>Hope this helps. Best, <br></div><div>Augustin<br></div><br><div><font color="#990099"><a href rel="noopener noreferrer nofollow" data-email-masked>----...@googlegroups.com</a> wrote: -----</font></div><div style="padding-left:5px"><div style="padding-right:0px;padding-left:5px;border-left:solid black 2px">To: "cp2k" <<a href rel="noopener noreferrer nofollow" data-email-masked>c...@googlegroups.com</a>><br>From: "Nicholas Winner" <u></u><br>Sent by: <a href rel="noopener noreferrer nofollow" data-email-masked>c...@googlegroups.com</a><br>Date: 10/28/2020 05:14PM<br>Subject: [CP2K:14133] MIX_CL_TRUNC + ADMM in cp2k development branch</div></div></font><font face="Default Sans Serif,Verdana,Arial,Helvetica,sans-serif" size="2"><div style="padding-left:5px"><div style="padding-right:0px;padding-left:5px;border-left:solid black 2px"><br><br>Hello all,<div><br></div><div>I need to make use of range separated hybrid functionals for periodic systems, so I have pulled the latest development version of cp2k from github which adds this support to admm module (in hfx_admm_utils.F).</div><div><br></div><div>To the best of my knowledge, I have implemented it correctly, but the difference in final energy between PBE0 and MIX_CL_TRUNC is ~7 Ha, which seems rather large. When going from GGA -> PBE0 the energy difference <1 Ha. Obviously there should be some change when changing the interaction potential, but this has me considered.</div><div><br></div><div><b>GGA: </b> ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.): -983.840366364871670 <b>PBE0</b> : ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.): -983.680119471562080</div><div><b>MIX_CL_TRUNC</b>: ENERGY| Total FORCE_EVAL ( QS ) energy [a.u.]: -974.290021294811368</div><div><br></div><div>Here is the XC section I am using to activate MIX_CL_TRUNC with ADMM. Can someone please sanity check and tell me if this is appropriate? </div><div><br></div><div><p> &XC</p>
<p> &XC_FUNCTIONAL PBE</p>
<p> &PBE</p>
<p> PARAMETRIZATION ORIG</p>
<p> SCALE_C 1</p>
<p> SCALE_X 0.665 # 1 - alpha - beta</p>
<p> &END PBE</p>
<p> &END XC_FUNCTIONAL</p>
<p> &HF</p>
<p> FRACTION 1</p>
<p> &SCREENING</p>
<p> EPS_SCHWARZ 1e-07</p>
<p> EPS_SCHWARZ_FORCES 1e-06</p>
<p> SCREEN_ON_INITIAL_P True</p>
<p> SCREEN_P_FORCES True</p>
<p> &END SCREENING</p>
<p> &INTERACTION_POTENTIAL</p>
<p> POTENTIAL_TYPE MIX_CL_TRUNC</p>
<p> CUTOFF_RADIUS 1.8</p>
<p> T_C_G_DATA t_c_g.dat</p>
<p> SCALE_LONGRANGE 0.085 # alpha</p>
<p> SCALE_COULOMB 0.25 # beta</p>
<p> OMEGA 0.94486</p>
<p> &END INTERACTION_POTENTIAL</p>
<p> &LOAD_BALANCE</p>
<p> RANDOMIZE True</p>
<p> &END LOAD_BALANCE</p>
<p> &MEMORY</p>
<p> EPS_STORAGE_SCALING 0.1</p>
<p> MAX_MEMORY 2000</p>
<p> &END MEMORY</p>
<p> &END HF</p>
<p> &END XC</p></div><div>Best,</div><div>Nicholas Winner</div>
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