<div dir="ltr">Hi,<div><br></div><div>I'm starting out with QE and am attempting to learn by repeating some literature results for hyperfine coupling constants for Li in Li2MnO3.</div><div><br></div><div>Capsoni et. al in 1997 Phys. Rev. B. list the experimental value for A as 4.31 MHz for one site (there are 2 other sites at essentially half that A)</div><div><br></div><div>Mali. et al. were able to reproduce that value very well in Chem. Comm. in 2010 (DOI:10.1039/c003065a) using QE with the GIPAW module.  I'm attempting to reproduce that result, following their method as close as possible.</div><div><br></div><div>I used dist.x to attempt to verify the structure, and did some convergence tests with respect to <span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">ecutwfc and k-points to make sure the calculations was reasonable. I also verified that the binary I have reproduced the H2O+ test case included in the distribution.</span></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">The result I get is quite a long ways off (0.06 MHz and -7 MHz instead of ~4.3 and ~2.15 MHz).</span></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">Any help on what I've managed to do wrong here would be greatly appreciated.</span></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><b>Input and relevant output below:</b></span></div><div><br></div><div>My scf input file (I swapped the <i>b</i> and <i>c</i> axes from the standard setting of the C2/m space group to use QE's convention for the unit cell face that has the extra lattice point in this non-primitive lattice):</div><div><br></div><div><div> &CONTROL</div><div>                 calculation = 'scf' ,</div><div>                restart_mode = 'from_scratch' ,</div><div>                      outdir = './scratch/' ,</div><div>                  pseudo_dir = './pseudo/' ,</div><div>                      prefix = 'Li2MnO3' ,</div><div>                   verbosity = 'high' ,</div><div> /</div><div> &SYSTEM</div><div>                       ibrav = 13,</div><div>                 space_group = 12,</div><div>                           A = 4.929200 ,</div><div>                           C = 8.531500 ,</div><div>                           B = 5.025100 ,</div><div>                       cosAC = 0 ,</div><div>                       cosAB = -0.33315 ,</div><div>                       cosBC = 0 ,</div><div>                         nat = 6,</div><div>                        ntyp = 3,</div><div>                     ecutwfc = 120.0 ,</div><div>                 occupations = 'smearing' ,</div><div>                     degauss = 0.02 ,</div><div>                    smearing = 'gaussian' ,</div><div>                       nspin = 2 ,</div><div>   starting_magnetization(2) = 0.7,</div><div>  /</div><div> &ELECTRONS</div><div>                    conv_thr = 1.0d-8 ,</div><div>                 mixing_mode = 'plain' ,</div><div>                 mixing_beta = 0.7 ,</div><div>             diagonalization = 'david' ,</div><div> /</div><div>ATOMIC_SPECIES</div><div>   Li    6.94100  Li.pbe-tm-gipaw-dc.upf</div><div>   Mn   54.93800  Mn.pbe-rrkj-semi-gipaw-dc.upf </div><div>    O   15.99900  O.pbe-tm-new-gipaw-dc.upf </div><div>ATOMIC_POSITIONS crystal_sg</div></div><div><div>ATOMIC_POSITIONS crystal_sg</div><div>Li       0.00     0.00     0.50</div><div>Li       0.00     0.50     0.00</div><div>Li       0.00     0.50     0.6606   </div><div>Mn       0.00     0.00     0.16708   </div><div>O        0.2189   0.2273   0.00</div><div>O        0.2540   0.2233   0.32119  </div><div>K_POINTS automatic </div><div>  4 4 4  1 1 1</div></div><div><br></div><div>gipaw input:</div><div><br></div><div><div>&inputgipaw</div><div>        job = 'hyperfine'</div><div>        prefix = 'Li2MnO3'</div><div>        tmp_dir = './scratch/'</div><div>        spline_ps = .true.</div><div>        verbosity = 'high'</div><div>        hfi_output_unit = 'MHz'</div><div>        hfi_nuclear_g_factor(1) = 2.170951 </div><div>/</div></div><div><br></div><div>The fermi-contact output is:</div><div><div>     ----- Fermi contact in MHz -----</div><div>               bare            GIPAW           core-relax      total</div><div>     Li   1      -15.412717       18.246446       -2.771682        0.062047</div><div>     Li   2      -15.450597        9.404951       -0.969447       -7.015093</div><div>     Li   3      -15.451374        9.237472       -0.964451       -7.178353</div><div>     Li   4      -15.451374        9.237473       -0.964451       -7.178352</div></div><div><br></div><div>-Kris Harris</div><div>Research Associate</div><div>McMaster University</div></div>