<div dir="ltr">Hi,<div><br></div><div>To use spin polarization, you should specify the keyword UKS in the DFT section and define a MULTIPLICITY.</div><div>You may also want to turn on RELAX_MULTIPLICITY in that section.</div>
<div class="gmail_extra"><br>To use a supercell, you can either manually repeat your coordinates and load the entire supercell as input coordinates, or specify MULTIPLE_UNIT_CELL in both the CELL and TOPOLOGY sections of the SUBSYS.</div>
<div class="gmail_extra">A 6x6x6 supercell should be okay to start out with, but you may want to check convergence.</div><div class="gmail_extra"><br></div><div class="gmail_extra">We have had decent experience with revPBE as an XC Functional for Ni [1]. BEEFvdW, a more recent addition to cp2k also gives very good bulk nickel, but it's currently somewhat of a beta-version and you need to compile with libxc to get it to work.</div>
<div class="gmail_extra"><br>Best, </div><div class="gmail_extra">Ralph</div><div class="gmail_extra"><br></div><div class="gmail_extra">[1] Gomez-Diaz et al, Theor Chim Acta, 2013</div><div class="gmail_extra"><br><div class="gmail_quote">
On Fri, Aug 15, 2014 at 2:24 PM, Alex <span dir="ltr"><<a href="mailto:nedo...@gmail.com" target="_blank">nedo...@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Also, I just redid the calculation with <div><br></div><div><div> <font face="courier new, monospace"> BASIS_SET DZV-GTH-PADE-q18</font></div><div><font face="courier new, monospace"> POTENTIAL GTH-PADE-q18</font></div>
<div><br></div><div>Same energy within I believe five decimal places. As far as the correct choice of the XC-potential-basis combination, what would be better in my case? As I've said before, I am really new to this... Any reference to that effect would be great.</div>
<div><br></div><div>Thank you.</div><div><div class="h5"><br>On Friday, August 15, 2014 3:05:37 PM UTC-6, Marcella Iannuzzi wrote:<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Hi<div><br></div><div>Just few remarks.</div><div><br></div><div>For the fcc bulk Ni energy, you need to construct a supercell, since there is no k-point sampling,</div><div>and check the convergence of the result with system size.</div>
<div><br></div><div>PADE is probably not an optimal choice for the XC functional, anyway, you should use consistent potential and basis set,</div><div>i.e. for the same number of valence electrons (in your input, the PP is for 10 v.e. and the BS for 18)</div>
<div><br></div><div>If you don't specify in in the input, no spin polarisation is considered.</div><div><br></div><div>Regards</div><div><br></div><div>Marcella</div><div> <br><br>On Friday, August 15, 2014 10:19:59 PM UTC+2, Alex wrote:<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi all,<div><br></div><div>I am very new to DFT calculations, let alone CP2k, so some level of idiocy on my part should be expected.</div><div>As a simple test, I am trying to calculate the binding energy of a Ni atom in a bulk crystal. The relevant portion of the input shown below:</div>
<div><br></div><div>***</div><div><div><font face="courier new, monospace">&GLOBAL</font></div><div><font face="courier new, monospace"> PROJECT Ni_inp_test</font></div><div><font face="courier new, monospace"> RUN_TYPE ENERGY_FORCE</font></div>
<div><font face="courier new, monospace"> PRINT_LEVEL LOW</font></div><div><font face="courier new, monospace">&END GLOBAL</font></div><div><font face="courier new, monospace">&FORCE_EVAL</font></div><div><font face="courier new, monospace"> METHOD Quickstep</font></div>
<div><font face="courier new, monospace"> &SUBSYS</font></div><div><font face="courier new, monospace"> &KIND Ni</font></div><div><font face="courier new, monospace"> ELEMENT<span style="white-space:pre-wrap"> </span>Ni</font></div>
<div><font face="courier new, monospace"> BASIS_SET DZV-GTH-PADE-q18</font></div><div><font face="courier new, monospace"> POTENTIAL GTH-PADE-q10</font></div><div><font face="courier new, monospace"> &END KIND</font></div>
<div><font face="courier new, monospace"> &CELL</font></div><div><font face="courier new, monospace"> A 1.765000 1.765000 0.000000</font></div><div><font face="courier new, monospace"> B 0.000000 1.765000 1.765000</font></div>
<div><font face="courier new, monospace"> C<span style="white-space:pre-wrap"> </span> 1.765000 0.000000 1.765000</font></div><div><font face="courier new, monospace"> PERIODIC<span style="white-space:pre-wrap"> </span>XYZ</font></div>
<div><font face="courier new, monospace"> &END CELL</font></div><div><font face="courier new, monospace"> &COORD</font></div><div><font face="courier new, monospace"> Ni 0.000000000 0.000000000 0.000000000</font></div>
<div><font face="courier new, monospace"> &END COORD</font></div><div><font face="courier new, monospace"> &END SUBSYS</font></div><div><font face="courier new, monospace"> &DFT</font></div><div><font face="courier new, monospace"> BASIS_SET_FILE_NAME BASIS_SET</font></div>
<div><font face="courier new, monospace"> POTENTIAL_FILE_NAME GTH_POTENTIALS</font></div><div><font face="courier new, monospace"> &QS</font></div><div><font face="courier new, monospace"> EPS_DEFAULT 1.0E-10</font></div>
<div><font face="courier new, monospace"> &END QS</font></div><div><font face="courier new, monospace"> &MGRID</font></div><div><font face="courier new, monospace"> NGRIDS 4</font></div><div><font face="courier new, monospace"> CUTOFF 300</font></div>
<div><font face="courier new, monospace"> REL_CUTOFF 60</font></div><div><font face="courier new, monospace"> &END MGRID</font></div><div><font face="courier new, monospace"> &XC</font></div><div><font face="courier new, monospace"> &XC_FUNCTIONAL PADE</font></div>
<div><font face="courier new, monospace"> &END XC_FUNCTIONAL</font></div><div><font face="courier new, monospace"> &END XC</font></div><div><font face="courier new, monospace"> &SCF</font></div><div>
<font face="courier new, monospace"> SCF_GUESS ATOMIC</font></div><div><font face="courier new, monospace"> EPS_SCF 1.0E-7</font></div><div><font face="courier new, monospace"> MAX_SCF 300</font></div><div>
<font face="courier new, monospace"> ADDED_MOS 10</font></div><div><font face="courier new, monospace"> &DIAGONALIZATION ON</font></div><div><font face="courier new, monospace"> ALGORITHM STANDARD</font></div>
<div><font face="courier new, monospace"> &END DIAGONALIZATION</font></div><div><font face="courier new, monospace"> &MIXING T</font></div><div><font face="courier new, monospace"> METHOD BROYDEN_MIXING</font></div>
<div><font face="courier new, monospace"> ALPHA 0.4</font></div><div><font face="courier new, monospace"> NBROYDEN 8</font></div><div><font face="courier new, monospace"> &END MIXING</font></div><div>
<font face="courier new, monospace"> &SMEAR ON</font></div><div><font face="courier new, monospace"> METHOD FERMI_DIRAC</font></div><div><font face="courier new, monospace"> ELECTRONIC_TEMPERATURE [K] 300</font></div>
<div><font face="courier new, monospace"> &END SMEAR</font></div><div><font face="courier new, monospace"> &END SCF</font></div><div><font face="courier new, monospace"> &END DFT</font></div><div><font face="courier new, monospace"> &PRINT</font></div>
<div><font face="courier new, monospace"> &FORCES ON</font></div><div><font face="courier new, monospace"> &END FORCES</font></div><div><font face="courier new, monospace"> &END PRINT</font></div><div>
<font face="courier new, monospace">&END FORCE_EVAL</font></div>
</div><div><font face="courier new, monospace"><br></font></div><div><font face="courier new, monospace">***</font></div><div><font face="courier new, monospace"><br></font></div><div><font face="courier new, monospace">This yields a total energy of E1=-35.155 a.u. after convergence.</font></div>
<div><font face="courier new, monospace"><br></font></div><div><font face="courier new, monospace">Then I decided to calculate the "vacuum" energy of an isolated atom, input below:</font></div><div><font face="courier new, monospace"><br>
</font></div><div><font face="courier new, monospace"><div>&GLOBAL</div><div> PROJECT Ni_inp_test</div><div> RUN_TYPE ENERGY_FORCE</div><div> PRINT_LEVEL LOW</div><div>&END GLOBAL</div><div>&FORCE_EVAL</div>
<div> METHOD Quickstep</div><div> &SUBSYS</div><div> &KIND Ni</div><div> ELEMENT<span style="white-space:pre-wrap"> </span>Ni</div><div> BASIS_SET DZV-GTH-PADE-q18</div><div> POTENTIAL GTH-PADE-q10</div>
<div> &END KIND</div><div> &CELL</div><div> A 30.00000 0.000000 0.000000</div><div> B 0.000000 30.00000 0.000000</div><div> C<span style="white-space:pre-wrap"> </span> 0.000000 0.000000 30.00000</div>
<div> &END CELL</div><div> &COORD</div><div> Ni 0.000000000 0.000000000 0.000000000</div><div> &END COORD</div><div> &END SUBSYS</div><div> &DFT</div><div> BASIS_SET_FILE_NAME BASIS_SET</div>
<div> POTENTIAL_FILE_NAME GTH_POTENTIALS</div><div> &QS</div><div> EPS_DEFAULT 1.0E-10</div><div> &END QS</div><div> &MGRID</div><div> NGRIDS 4</div><div> CUTOFF 300</div><div> REL_CUTOFF 60</div>
<div> &END MGRID</div><div> &XC</div><div> &XC_FUNCTIONAL PADE</div><div> &END XC_FUNCTIONAL</div><div> &END XC</div><div> &SCF</div><div> SCF_GUESS ATOMIC</div><div> EPS_SCF 1.0E-7</div>
<div> MAX_SCF 300</div><div> ADDED_MOS 10</div><div> &DIAGONALIZATION ON</div><div> ALGORITHM STANDARD</div><div> &END DIAGONALIZATION</div><div> &MIXING T</div><div> METHOD BROYDEN_MIXING</div>
<div> ALPHA 0.4</div><div> NBROYDEN 8</div><div> &END MIXING</div><div> &SMEAR ON</div><div> METHOD FERMI_DIRAC</div><div> ELECTRONIC_TEMPERATURE [K] 300</div><div> &END SMEAR</div>
<div> &END SCF</div><div> &END DFT</div><div> &PRINT</div><div> &FORCES ON</div><div> &END FORCES</div><div> &END PRINT</div><div>&END FORCE_EVAL</div><div><br></div><div>***</div>
<div>
<br></div><div>This also converges and yields a total energy E2=-34.555 a.u.</div><div><br></div><div><br></div><div>Hence, my questions:</div><div><br></div><div>1. Is this even the correct way of calculating what I want, including the energy calculations, XC functional, and basis?</div>
<div>2. Should the spin properties be explicitly set in the input? There are none now.</div><div>3. Am I setting up the FCC lattice correctly (first input file)? My translation vectors are set by the ABC values, but I have no idea whether this is right.</div>
<div>4. If the first simulation yields the total energy of the system and the FCC lattice implies 12 nearest neighbors, then removing the center would change the total energy by (E1-E2)/6, which isn't the experimental -4.4 eV. Am I completely off track here? :)</div>
<div><br></div><div>Thanks a lot!</div></font></div></blockquote></div></div></blockquote></div></div></div></div><div class="HOEnZb"><div class="h5">
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