Dear David,<div><br></div><div>You are right in that the Lowdin charges here refer to the valence electrons of your system. </div><div><br></div><div>The Lowdin charges are calculated as a sum of the projections of the extended plane wave valence states onto a pseudo-atomic basis (characterized by the highest valence s, p, d, f states per your output). </div>
<div><br></div><div>The numbers are positive and not negative, as you pointed out, because they refer to the *number* of electrons (i.e. s, p, and so on). In your example, there appears to be approximately four electrons: 1 s-type and 3 p-type valence electrons attributed to each atom. </div>
<div><br></div><div>The code should also a 'spilling parameter' at the bottom of your output that tells you how well the projections are capturing the description of the valence states. For instance, the projection is capturing 3.96 electrons per atom in your example. So, if you expect in your example to have four valence electrons per atom, then the pseudo-atomic basis is capturing your extended valence states pretty well.</div>
<div><br></div><div>Hope that helps!</div><div>--</div><div>Heather K</div><div>Postdoc at Stanford University</div><div> </div><div><div class="gmail_quote">On Fri, Dec 10, 2010 at 5:54 PM, David Grifith <span dir="ltr"><<a href="mailto:david.grifith@gmail.com" target="_blank">david.grifith@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear QE Users<br><br>My calculated "Lowdin Charge" values are "positive" as shown below. I thought that they must be the charge of the valence electron ! but the sign is positive. Also, I don't know that a pseudopotential package like Quantum Espresso considers the "core" charge to be calculated or not ? <br>
<br><br><br> Atom # 1: total charge = 3.9571, s = 0.9145, p = 3.0426, d = 0.0000, <br> spin up = 1.9786, s = 0.4573, p = 1.5213, d = 0.0000, <br> spin down = 1.9786, s = 0.4573, p = 1.5213, d = 0.0000, <br>
polarization = 0.0000, s = 0.0000, p = 0.0000, d = 0.0000, <br> Atom # 2: total charge = 3.9569, s = 0.9154, p = 3.0415, d = 0.0000, <br> spin up = 1.9785, s = 0.4577, p = 1.5208, d = 0.0000, <br>
spin down = 1.9785, s = 0.4577, p = 1.5208, d = 0.0000, <br> polarization = 0.0000, s = 0.0000, p = 0.0000, d = 0.0000, <br> Atom # 3: total charge = 3.9554, s = 0.9153, p = 3.0402, d = 0.0000, <br>
spin up = 1.9777, s = 0.4576, p = 1.5201, d = 0.0000, <br> spin down = 1.9777, s = 0.4576, p = 1.5201, d = 0.0000, <br> polarization = 0.0000, s = 0.0000, p = 0.0000, d = 0.0000, <br>
Atom # 4: total charge = 3.9573, s = 0.9164, p = 3.0408, d = 0.0000, <br> spin up = 1.9786, s = 0.4582, p = 1.5204, d = 0.0000, <br> spin down = 1.9786, s = 0.4582, p = 1.5204, d = 0.0000, <br>
polarization = 0.0000, s = 0.0000, p = 0.0000, d = 0.0000, <br> Atom # 5: total charge = 3.9607, s = 0.9155, p = 3.0452, d = 0.0000, <br> spin up = 1.9804, s = 0.4578, p = 1.5226, d = 0.0000, <br>
spin down = 1.9804, s = 0.4578, p = 1.5226, d = 0.0000, <br> polarization = -0.0000, s = -0.0000, p = -0.0000, d = 0.0000, <br> Atom # 6: total charge = 3.9599, s = 0.9146, p = 3.0453, d = 0.0000, <br>
spin up = 1.9800, s = 0.4573, p = 1.5227, d = 0.0000, <br> spin down = 1.9800, s = 0.4573, p = 1.5227, d = 0.0000, <br> polarization = -0.0000, s = -0.0000, p = -0.0000, d = 0.0000, <br>
Atom # 7: total charge = 3.9600, s = 0.9148, p = 3.0452, d = 0.0000, <br> spin up = 1.9800, s = 0.4574, p = 1.5226, d = 0.0000, <br> spin down = 1.9800, s = 0.4574, p = 1.5226, d = 0.0000, <br>
polarization = -0.0000, s = -0.0000, p = -0.0000, d = 0.0000, <br clear="all"><font color="#888888"><br>-- <br>Sincerely Yours<br>David G.<br>JCU<br><br>
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