As a follow up on my previous post, I let the calculation run to completion on a less dense k-grid and saw the following output:
ik 2 ibnd 17 linter: root not converged 0.748E+35 > kpoint 2 ibnd 17 pcgreen: root not converged 0.421E+23 > Non-scf u_k: avg # of iterations =137.0 > Non-scf Du_k: avg # of iterations =200.0 > > Dielectric constant from finite-differences > > ( NaN NaN NaN ) > ( NaN NaN NaN ) > ( NaN NaN NaN ) > > Computing Second order response > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > > > iter # 1 av.it.: 147.2 > thresh= 0.100E-01 alpha_mix = 0.100 |ddv_scf|^2 = NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > kpoint 2 ibnd 17 pcgreen: root not converged NaN > > > iter # 2 av.it.: 200.0 > thresh= 0.100E-01 alpha_mix = 0.100 |ddv_scf|^2 = NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > kpoint 1 ibnd 17 pcgreen: root not converged NaN > > > and so on. The code crashes at the end with the error: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > from broyden : error # 1 > factorization > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > > but obviously the problem occurs well before this crash. Again, I am trying to calculate the Raman intensity for a material with a small indirect overlap. Should this not be possible? I know that DFPT is applicable (without modification) only for systems with a clear distinction between occupied and valence states (in order to clearly specify what the projectors over the occupied and unoccupied manifolds I guess?). For the indirect overlap case with fixed occupancies I would imagine that this would be possible. Anyway, just wanted to report on the results of my first post. If anyone knows what I can do to calculate the intensity or simply if it should or shouldn't work (and/or "why") I would greatly appreciate it. Best, Brad Malone UC Berkeley On Sun, Nov 22, 2009 at 11:36 AM, Brad Malone <brad.malone at gmail.com> wrote: > Hi, I'm interested in calculating the Raman intensity for a material with a > small indirect band overlap within LDA (~0.3 eV). As has been mentioned many > times on this forum, Raman intensities cannot be calculated for a pure > metal. But should I expect to be able to calculate the intensity for a > material with a small, indirect band overlap? When I attempted to do so > (using lraman=.true. in the ph.x calculation) I received the following > messages: > > Computing Pc [DH,Drho] |psi> >> >> Derivative coefficient: 0.001000 Threshold: 1.00E-12 >> ik 1 ibnd 17 linter: root not converged 0.578E+08 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.763E+05 >> ik 1 ibnd 17 linter: root not converged 0.193E+11 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.119E+05 >> ik 1 ibnd 17 linter: root not converged 0.595E+09 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.182E+05 >> ik 1 ibnd 17 linter: root not converged 0.142E+31 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.224E+24 >> ik 1 ibnd 17 linter: root not converged 0.143E+30 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.170E+25 >> ik 1 ibnd 17 linter: root not converged 0.765E+28 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.151E+25 >> ik 1 ibnd 17 linter: root not converged 0.643E+09 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.460E+05 >> ik 1 ibnd 17 linter: root not converged 0.619E+10 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.547E+07 >> ik 1 ibnd 17 linter: root not converged 0.685E+09 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.810E+04 >> ik 1 ibnd 17 linter: root not converged 0.290E+34 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.848E+19 >> ik 1 ibnd 17 linter: root not converged 0.132E+33 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.333E+18 >> ik 1 ibnd 17 linter: root not converged 0.155E+34 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.133E+20 >> ik 1 ibnd 17 linter: root not converged 0.146E+06 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.442E+05 >> ik 1 ibnd 17 linter: root not converged 0.135E+07 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.169E+06 >> ik 1 ibnd 17 linter: root not converged 0.567E+08 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.493E+06 >> ik 1 ibnd 17 linter: root not converged 0.292E+27 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.518E+23 >> ik 1 ibnd 17 linter: root not converged 0.882E+28 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.215E+24 >> ik 1 ibnd 17 linter: root not converged 0.104E+29 >> kpoint 1 ibnd 17 pcgreen: root not converged 0.328E+23 >> ik 2 ibnd 17 linter: root not converged 0.585E+21 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.363E+23 >> ik 2 ibnd 17 linter: root not converged 0.505E+21 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.119E+22 >> ik 2 ibnd 17 linter: root not converged 0.117E+21 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.267E+22 >> ik 2 ibnd 17 linter: root not converged 0.159E+33 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.283E+27 >> ik 2 ibnd 17 linter: root not converged 0.367E+32 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.660E+27 >> ik 2 ibnd 17 linter: root not converged 0.876E+32 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.670E+28 >> ik 2 ibnd 17 linter: root not converged 0.249E+32 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.125E+28 >> ik 2 ibnd 17 linter: root not converged 0.348E+31 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.206E+26 >> ik 2 ibnd 17 linter: root not converged 0.141E+30 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.561E+25 >> ik 2 ibnd 17 linter: root not converged 0.520E+36 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.990E+24 >> ik 2 ibnd 17 linter: root not converged 0.140E+37 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.721E+24 >> ik 2 ibnd 17 linter: root not converged 0.836E+35 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.690E+25 >> ik 2 ibnd 17 linter: root not converged 0.246E+30 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.540E+24 >> ik 2 ibnd 17 linter: root not converged 0.517E+29 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.415E+25 >> ik 2 ibnd 17 linter: root not converged 0.133E+30 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.202E+26 >> ik 2 ibnd 17 linter: root not converged 0.570E+27 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.103E+21 >> ik 2 ibnd 17 linter: root not converged 0.270E+29 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.451E+22 >> ik 2 ibnd 17 linter: root not converged 0.381E+29 >> kpoint 2 ibnd 17 pcgreen: root not converged 0.346E+22 >> ik 3 ibnd 17 linter: root not converged 0.118E+34 >> > > and so on for each ik in the calculation. The code never crashed and I > stopped it prematurely due to concern about these messages (seeing values on > the order of 1E+34 is never calming). The code was also taking a very long > time to calculate each ik. From what I've read in the Lazzeri and Mauri > paper (PRL 90, 036401, 2003) some of the methods used to calculate the Raman > tensor can take a lot of linear response calculations and so maybe I > shouldn't expect it to go extremely fast. However, this root convergence > worries me. The 17th band, which is the only band that this problem occurs > for that I've seen, is the first conduction band of the system and is the > band that indirectly overlaps with the top of the valence band. Any help or > comments would be greatly appreciated! > > Thanks, > Brad Malone > UC Berkeley > > P.S. I used 'fixed' occupancies in the SCF run to avoid the 'elec. field' > error in the ph.x calculation. The fixed occupancy is what I would expect > for this material in experiment, as the GW bandstructure for this material > predicts it to be semiconducting. > > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20091130/f59d0d5a/attachment-0002.html
