http://www.democritos.it/pipermail/pw_forum/2008-September/010123.html http://www.democritos.it/pipermail/pw_forum/2010-February.txt
I understand that the third derivatives were never implemented and that only the LDA part was calculated, for the Perdew Zunger parameterization. Is this third derivative the third derivative that is mentioned in the routine PH/raman_mat.f90 (i.e, the third derivative of the energy with respect to the atomic displacements and with respect to two electric fields, as described in Lazzeri and Mauri, PRL 90,036401)? I am interested in getting a feel for what would be needed to implement the third derivatives with GGA into the code, as well as what sort of errors one might expect when using the third-order term as currently coded with LDA pseudopotentials (comments in the forums have hinted that the errors are likely small). The shift in the Raman spectra for cd-Si is pretty minor when using a GGA pseudo compared to that of an LDA calculation, but I wanted to be able to quantify the error better for other systems where comparing the GGA raman spectra to one calculated within LDA was not possible (e.g., when the system doesn't exhibit a gap in LDA). Thanks for the help! Best, Brad UC Berkeley On Tue, Nov 9, 2010 at 5:59 PM, Brad Malone <brad.malone at gmail.com> wrote: > It appears that my last email was severely truncated on the mailing list > (even though it looks fine in my outbox). Below is what is should have been: > ----------------------- > Hi, I am seeking more information on the error > > > from phq_setup : error # 1 > > third order derivatives not implemented with GGA > > From the forums: > > http://www.democritos.it/pipermail/pw_forum/2008-September/010123.html > http://www.democritos.it/pipermail/pw_forum/2010-February.txt > > I understand that the third derivatives were never implemented and > that only the LDA part was calculated, for the Perdew Zunger > parameterization. Is this third derivative the third derivative that > is mentioned in the routine PH/raman_mat.f90 (i.e, the third > derivative of the energy with respect to the atomic displacements and > with respect to two electric fields, as described in Lazzeri and > Mauri, PRL 90,036401)? > > I am interested in getting a feel for what would be needed to > implement the third derivatives with GGA into the code, as well as > what sort of errors one might expect when using the third-order term > as currently coded with LDA pseudopotentials (comments in the forums > have hinted that the errors are likely small). The shift in the Raman > spectra for cd-Si is pretty minor when using a GGA pseudo compared to > that of an LDA calculation, but I wanted to be able to quantify the > error better for other systems where comparing the GGA raman spectra > to one calculated within LDA was not possible (e.g., when the system > doesn't exhibit a gap in LDA). > > Thanks for the help! > > Best, > Brad > UC Berkeley > > On Tue, Nov 9, 2010 at 5:00 PM, Brad Malone <brad.malone at gmail.com> wrote: > >> Hi, I am seeking more information on the error >> >> > from phq_setup : error # 1 >> > third order derivatives not implemented with GGA >> >> From the forums: >> >> http://www.democritos.it/pipermail/pw_forum/2008-September/010123.html >> http://www.democritos.it/pipermail/pw_forum/2010-February.txt >> >> I understand that the third derivatives were never implemented and >> that only the LDA part was calculated, for the Perdew Zunger >> parameterization. Is this third derivative the third derivative that >> is mentioned in the routine PH/raman_mat.f90 (i.e, the third >> derivative of the energy with respect to the atomic displacements and >> with respect to two electric fields, as described in Lazzeri and >> Mauri, PRL 90,036401)? >> >> I am interested in getting a feel for what would be needed to >> implement the third derivatives with GGA into the code, as well as >> what sort of errors one might expect when using the third-order term >> as currently coded with LDA pseudopotentials (comments in the forums >> have hinted that the errors are likely small). The shift in the Raman >> spectra for cd-Si is pretty minor when using a GGA pseudo compared to >> that of an LDA calculation, but I wanted to be able to quantify the >> error better for other systems where comparing the GGA raman spectra >> to one calculated within LDA was not possible (e.g., when the system >> doesn't exhibit a gap in LDA). >> >> Thanks for the help! >> >> Best, >> Brad >> UC Berkeley >> > > --000e0cd1e7da89ad9c0494a93ee2 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable No idea why it is being truncated, so this time I'll start the email af= ter the error message<div>---------------</div><div><div>From the forums:</= div><div><br></div><div><a href=3D"http://www.democritos.it/pipermail/pw_fo= rum/2008-September/010123.html">http://www.democritos.it/pipermail/pw_forum= /2008-September/010123.html</a></div> <div><a href=3D"http://www.democritos.it/pipermail/pw_forum/2010-February.t= xt">http://www.democritos.it/pipermail/pw_forum/2010-February.txt</a></div>= <div><br></div><div>I understand that the third derivatives were never impl= emented and</div> <div>that only the LDA part was calculated, for the Perdew Zunger</div><div= >parameterization. Is this third derivative the third derivative that</div>= <div>is mentioned in the routine PH/raman_mat.f90 (i.e, the third</div> <div>derivative of the energy with respect to the atomic displacements and<= /div><div>with respect to two electric fields, as described in Lazzeri and<= /div><div>Mauri, PRL 90,036401)?</div><div><br></div><div>I am interested i= n getting a feel for what would be needed to</div> <div>implement the third derivatives with GGA into the code, as well as</di= v><div>what sort of errors one might expect when using the third-order term= </div><div>as currently coded with LDA pseudopotentials (comments in the fo= rums</div> <div>have hinted that the errors are likely small). =A0The shift in the Ram= an</div><div>spectra for cd-Si is pretty minor when using a GGA pseudo comp= ared to</div><div>that of an LDA calculation, but I wanted to be able to qu= antify the</div> <div>error better for other systems where comparing the GGA raman spectra</= div><div>to one calculated within LDA was not possible (e.g., when the syst= em</div><div>doesn't exhibit a gap in LDA).</div><div><br></div><div> Thanks for the help!</div><div><br></div><div>Best,</div><div>Brad</div><di= v>UC Berkeley</div></div><div><div><br></div><br><div class=3D"gmail_quote"= >On Tue, Nov 9, 2010 at 5:59 PM, Brad Malone <span dir=3D"ltr"><<a href= =3D"mailto:brad.malone at gmail.com">brad.malone at gmail.com</a>></span> wrot= e:<br> <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p= x #ccc solid;padding-left:1ex;">It appears that my last email was severely = truncated on the mailing list (even though it looks fine in my outbox). Bel= ow is what is should have been:<div> -----------------------</div><div><div><div></div><div class=3D"h5"><span s= tyle=3D"font-family:arial, sans-serif;font-size:13px;border-collapse:collap= se;color:rgb(51, 51, 51)">Hi, I am seeking more information on the error<br= > <br>> from phq_setup : error # 1<br>> third order derivatives not imp= lemented with GGA<br><br>From the forums:<br><br><a href=3D"http://www.demo= critos.it/pipermail/pw_forum/2008-September/010123.html" style=3D"color:rgb= (61, 84, 89)" target=3D"_blank">http://www.democritos.it/pipermail/pw_forum= /2008-September/010123.html</a><br> <a href=3D"http://www.democritos.it/pipermail/pw_forum/2010-February.txt"; s= tyle=3D"color:rgb(61, 84, 89)" target=3D"_blank">http://www.democritos.it/p= ipermail/pw_forum/2010-February.txt</a><br><br>I understand that the third = derivatives were never implemented and<br> that only the LDA part was calculated, for the Perdew Zunger<br>parameteriz= ation. Is this third derivative the third derivative that<br>is mentioned i= n the routine PH/raman_mat.f90 (i.e, the third<br>derivative of the energy = with respect to the atomic displacements and<br> with respect to two electric fields, as described in Lazzeri and<br>Mauri, = PRL 90,036401)?<br><br>I am interested in getting a feel for what would be = needed to<br>implement the third derivatives with GGA into the code, as wel= l as<br> what sort of errors one might expect when using the third-order term<br>as = currently coded with LDA pseudopotentials (comments in the forums<br>have h= inted that the errors are likely small). =A0The shift in the Raman<br>spect= ra for cd-Si is pretty minor when using a GGA pseudo compared to<br> that of an LDA calculation, but I wanted to be able to quantify the<br>erro= r better for other systems where comparing the GGA raman spectra<br>to one = calculated within LDA was not possible (e.g., when the system<br>doesn'= t exhibit a gap in LDA).<br> <br>Thanks for the help!<br><br>Best,<br>Brad<br>UC Berkeley</span><br><br>= </div></div><div><div></div><div class=3D"h5"><div class=3D"gmail_quote">On= Tue, Nov 9, 2010 at 5:00 PM, Brad Malone <span dir=3D"ltr"><<a href=3D"= mailto:brad.malone at gmail.com" target=3D"_blank">brad.malone at gmail.com</a>&g= t;</span> wrote:<br> <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p= x #ccc solid;padding-left:1ex">Hi, I am seeking more information on the err= or<br> <br> > from phq_setup : error # 1<br> > third order derivatives not implemented with GGA<br> <br>
