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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Dear PWSCF forum,<o:p></o:p></p><p class=MsoNormal>I want to calculate the average value of the position operator in the gamma->X direction for several k-points in an orthorhombic supercell. Directly using wavefunctions has given me a huge amount of trouble so now I wish to try doing so using thecharge density n_{j,k}(x). The system is not spin polarized. Perhaps this is me being dumb, but the documentation leaves me unclear as to how to do this. <o:p></o:p></p><p class=MsoNormal>Does one use pp.x or plotrho.x to accomplish this?<o:p></o:p></p><p class=MsoNormal>If one must use plotrho.x is there an input file description online anywhere? I looked and didn’t find one<o:p></o:p></p><p class=MsoNormal>If one uses pp.x what is the correct combination of options? I have tried plot num = 0 which did not allow me to specify the band number or kpoint.<o:p></o:p></p><p class=MsoNormal>I also tried plotnum = 7. It was unclear to me what data I was actually generating. When one specifies the kpoint as an integer how does one correlate which kpoint they are plotting for with the integer they enter? Is the gamma point represented as 0 or as 1? Since I want the charge density along the x direction do I set the spin_component = 1 despite the fact that I have set this as a an unpolarized case? <br><br>What are the units in the output and what does each column represent? There seems to be no listing in the documentation, or is it included in the output when I was using a gnuplot 1D output.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sorry for the long winded question, but I am really a bit lost on this at the moment. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Robert Hembree<o:p></o:p></p><p class=MsoNormal>QTP<o:p></o:p></p></div></body></html>