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<p class="MsoNormal"><span style="color:black">Dear all,</span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> </span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">Recently I am using Environ + QE to calculate the work function of Mg(0001) surface in different environment (vacuum/implicit water). Firstly I was doing a geometry optimisation calculation of Mg(0001) slab without
environment packages. In this case, the fermi energy of the slab is -0.2249 eV and the vacuum potential is around 3.4713 eV(obtained using the pp.x and avg.x). Therefore, the work function can be simply calculated using 3.4713 – (-0.2249) = 3.6962 eV (which
is close to the reference value: 3.62 eV).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:black">Then I use the environment packages and turn on the implicit model, the input file for the environment part is as follows:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:black">&ENVIRON<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> !<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> verbose = 0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> environ_thr = 1.D0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> environ_type = 'input'<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> env_static_permittivity = 78.3(water)/1(vacuum)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> env_surface_tension = 0.D0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> env_pressure = 0.D0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> env_electrostatic = .true.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> !<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">/<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">&BOUNDARY<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> !<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> solvent_mode = 'full'<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> !<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">/<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">&ELECTROSTATIC<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> !<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> pbc_correction = 'parabolic'<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> pbc_dim = 2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> pbc_axis = 3<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> tol = 5.D-13<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> !<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">/ </span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">The calculations for the slab in vacuum/water were done without any errors. However, in the vacuum case, the fermi energy (considering the parabolic correction) of the slab is -3.2031 + 0.4671 = -2.736 eV. The
vacuum (enviroment) potential is 3.105 eV (using pp.x and avg.x). The work function is vacuum with the environment package is 3.105 - (-2.736) = 5.841 eV, which is not correct. I guess this error answer is due to the wrong vacuum potential. That is to say,
the environment potential in this case should not calculate in the normal way (pp.x + avg.x) or the environment potential should be corrected in some way. However, I have no idea about how to obtain the correct environment(vacuum/water) potential when the
environment packages are used. I was wondering that could anyone who knows how to calculate the work function of the metal slab in the implicit environment correctly please help me on this issue?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:black">I am looking forward to your reply.</span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"> </span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">Best Regards,</span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">Bingxin </span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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