[Pw_forum] The symmetry of bands
Thank you for your help concerning plotband.x and bands.x. 2009/4/3 Gabriele Sclauzero > > > > > My questions are: > > 1. Why the calculated top of valence bands (15th, and 16th ) do not > > split as reported work (Appl. Phys. Lett.83,5163)? > > 2. In the spin.dat.rap file, what does the symbol "T" stand for? And > > what does the "1 2 5 6 5 6 5 ..." > mean? > > I can reply to the second, for the moment: > T is a flag, needed by plotband.x program, which identifies k-point which > have a different > symmetry with respect to the preceeding. It is meant to identify the > special k-point in > your k-point path used for plotting the bands. Since you have only one > k-point in this > calculation, you should not worry about this flag. > > The numbers on the rows are the representations to which the corresponding > eigenvalues > (those listed in the filband file) belong. The representations are listed > in the standard > output of bands.x, so that to each number you can associate an irreducible > representation. > > GS > > > The calculated results of the band structure at Gamma point is as > following: > > spin.dat: > > &plot nbnd= 30, nks= 1 / > > 0.00 0.00 0.00 > > -8.070 -8.070 -5.968 -5.968 1.092 1.092 6.154 6.154 > > 6.169 6.169 > >6.803 6.803 6.816 6.816 7.015 7.015 11.136 11.136 > > 13.603 13.603 > > 17.513 17.513 18.094 18.094 18.118 18.118 19.967 19.967 > > 20.042 20.042 > > > > spin.dat.rap: > > &plot_rap nbnd_rap= 30, nks_rap= 1 / > > 0.00 0.00 0.00T > >1 2 5 6 5 6 5 6 > > 3 4 > >1 2 3 4 1 2 1 2 > > 5 6 > >5 6 1 2 3 4 1 2 > > 5 6 > > > > -- > > > o o > | Gabriele Sclauzero, PhD Student | > | c/o: SISSA & CNR-INFM Democritos, | > |via Beirut 2-4, 34014 Trieste (Italy) | > | email: sclauzer at sissa.it | > | phone: +39 040 3787 511 | > | skype: gurlonotturno | > o o > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Y. C. Cheng Department of Phyics Nanjing University Nanjing 210093 P. R. China Tel: 86-25-83592907 Email: yccheng.nju at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090403/23dfeede/attachment.htm
[Pw_forum] The symmetry of bands
N0.7 0.3 0.879371803 > > Al 0.3 0.7 -0.002269507 > > Al 0.7 0.3 0.497730493 > > K_POINTS automatic > > 4 4 4 1 1 1 > > band.in > > &control > > title = 2h_aln, > > prefix = '2h_band', > > calculation = 'bands' , > > restart_mode = 'from_scratch' , > > wf_collect = .false. , > > outdir = './' , > > wfcdir = './' , > > pseudo_dir = './' , > > / > > &SYSTEM > >ibrav = 4, > >celldm(1) = 5.904838149212, > >celldm(3) = 1.603024550651, > > nat = 4, > > ntyp = 2, > > ecutwfc = 80, > > occupations='fixed', > > nbnd=30, > > lspinorb = .true., > > noncolin= .true., > >starting_magnetization=0.00, > > / > > &ELECTRONS > > electron_maxstep = 100, > > conv_thr = 1.D-12, > > / > > ATOMIC_SPECIES > > N 14.00700 N.rel-pbe-rrkjus.UPF > >Al 26.98200 Al.rel-pbe-rrkj.UPF > > ATOMIC_POSITIONS (crystal) > > N0.3 0.7 0.379371803 > > N0.7 0.3 0.879371803 > > Al 0.3 0.7 -0.002269507 > > Al 0.7 0.3 0.497730493 > > K_POINTS > > 1 > > 0.00 0.00 0.00 1.00 > > > > bands.in for bands.x to get band symmetry information > > > > &inputpp > > prefix='2h_band' > > outdir='./' > > filband='spin.dat' > > lsigma(3)=.true. > > lsym=.true. > > / > > The calculated results of the band structure at Gamma point is as > > following: > > spin.dat: > > &plot nbnd= 30, nks= 1 / > > 0.00 0.00 0.00 > > -8.070 -8.070 -5.968 -5.968 1.092 1.092 6.154 6.154 > > 6.169 6.169 > >6.803 6.803 6.816 6.816 7.015 7.015 11.136 11.136 > > 13.603 13.603 > > 17.513 17.513 18.094 18.094 18.118 18.118 19.967 19.967 > > 20.042 20.042 > > > > spin.dat.rap: > > &plot_rap nbnd_rap= 30, nks_rap= 1 / > > 0.00 0.00 0.00T > >1 2 5 6 5 6 5 6 > > 3 4 > >1 2 3 4 1 2 1 2 > > 5 6 > >5 6 1 2 3 4 1 2 > > 5 6 > > > > My questions are: > > 1. Why the calculated top of valence bands (15th, and 16th ) do not > > split as reported work (Appl. Phys. Lett.83,5163)? > > 2. In the spin.dat.rap file, what does the symbol "T" stand for? And > > what does the "1 2 5 6 5 6 5 ..." > > mean? > > > > Thank you in advance! > > > > -- > > Y. C. Cheng > > Department of Physics > > Nanjing University > > Nanjing 210093 > > P. R. China > > Tel: 86-25-83592907 > > Email: yccheng.nju at gmail.com > > > > ___ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://www.democritos.it/mailman/listinfo/pw_forum > -- > Andrea Dal CorsoTel. 0039-040-3787428 > SISSA, Via Beirut 2/4 Fax. 0039-040-3787528 > 34014 Trieste (Italy) e-mail: dalcorso at sissa.it > > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Y. C. Cheng Department of Physics Nanjing University Nanjing 210093 P. R. China Tel: 86-25-83592907 Email: yccheng.nju at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090403/a8ab9b36/attachment-0001.htm
[Pw_forum] Xcrysden
On Fri, Apr 3, 2009 at 7:43 PM, S. K. S. wrote: > Dear Users, > > I have a couple of questions regarding Xcrysden. > 1. Usually xcrysden files use the following format: > > PRIMVEC >5.52460788000.000.00 >0.003.90648780400.00 >0.000.00 19.5324384880 > PRIMCOORD > 14 1 > 31 0.3031580950 0.00-0.3114762280 > 31 2.6436116560 1.9532436370-1.8580462820 > 31 -0.0518106620 0.00-3.8817233780 > 31 2.7623039400 1.9532436370-5.8597314410 > 31 0.00 0.00-7.8129756070 > 31 2.7623039400 1.9532436370-9.7662192440 > 33 1.4763662580 1.9532436370 0.3364242780 > > where atomic positions are not written in crystal co-ordinates. > Is it possible to specify atomic positions in crystal co-ordinates in any > of .xyz or .xsf xcrysden input files (except .pwi or .pwo files). > Yes, you can, please have a look at the format of XSF file. > > 2. How to print the thermometer in Xcrysden??? > Everytime I get an error saying "could not execute /usr/bin/convert". > You should install GIMP, a GNU image processor. > > I'll be highly obliged if anyone kindly discuss the above issues. > regards, > SKS > JNCASR > Bangalore > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Hai-Ping Lan Department of Electronics , Peking University , Bejing, 100871 lanhaiping at gmail.com, hplan at pku.edu.cn -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090403/bccfe097/attachment.htm
[Pw_forum] Xcrysden
Dear all, Thanks a lot for your kind and helpful reply. Few things about Xcrysden are yet to be known. 1. Now I can print the thermometer after installing ImageMagick. However, it prints the thermometer separately. Please have a look on the attached file. Is it possible in XCrysden to print the thermometer together with the background "Xcrysden charge-density" plot 2. >No! XSF uses Carthesian coordinates (Angstrom units). Then, is there any other smart way to change Angstrom coordinates to crystal coordinates in Xcrysden??? The usual pen and paper (analytical and manual) method is not always time-saving especially for non-cubic (for instance, hexagonal) systems. 3. Another thing I would like to know, whether it is possible to increase the size of the "XYZ co-ordinate symbol" in Xcrysden??? One can easily zoom the picture of a molecule or a crystal in the Xcrysden and print the larger size picture because Xcrysden's print is an XWD window dump. But what about co-ordinate symbol??? Is it possible to make its size bigger? regards, SKS -- next part -- A non-text attachment was scrubbed... Name: mol-urea2D.jpg Type: image/jpeg Size: 4822 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20090403/fe5fcd38/attachment-0001.jpg
[Pw_forum] PP for Planar average of all |psi|^2
Dear Paul,
sujata Paul wrote:
> Hi Gabriele,
> This is regarding the calculation of Planar Average of
> |psi^2| using "PP/plan_avg.f90". So according to your suggestion I tried
> this input file:
> =
> &inputpp
> prefix='CO2',
> outdir './'
> filplot = 'CO2-psi-plan_avg.pot'
> /
> =
>
> Before that I did SCF calculations using Gamma Kpoint.
> "K_POINTS {automatic}
> 1 1 1 0 0 0"
>
> With this recipe the error I got is this:
>
> from plan_avg : error # 2
> planar average with gamma tricks not yet implemented
>
That's strange, as far as I know gamma triks are used only if you specify
K_POINTS GAMMA
The gamma_only flag should be enabled only when using this K_POINTS setting.
Please verify
if this is true (you can examine the data-file.xml in your .save directory or
add a print
statement).
GS
> So I can't calculate |psi^2| planar average for
> k= (0.000 0.000 0.000)?
>
> Thanks and Regards
> --
> SUJATA PAUL
> GRADUATE STUDENT
> PHYSICS DEPARTMENT
> NORTH CAROLINA STATE UNIVERSITY
> USA
>
>
>
> It was written in the error message you posted at the beginning:
>
> %%
> from punch_plot : error # 1
> no longer implemented, see PP/plan_avg.f90
> %%
> So I guessed "plot_num=9" is not implemented in post processing.
>
> You have to use the program plan_avg.x in place of pp.x for this task.
> Though I never used it, from a glance to the source I guess it should be
> simple to use:
>
> NAMELIST / inputpp / outdir, prefix, filplot
>
> You simply need to specify these three strings...
>
>
> GS
>
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
--
o o
| Gabriele Sclauzero, PhD Student |
| c/o: SISSA & CNR-INFM Democritos, |
|via Beirut 2-4, 34014 Trieste (Italy) |
| email: sclauzer at sissa.it |
| phone: +39 040 3787 511 |
| skype: gurlonotturno |
o o
[Pw_forum] Xcrysden
Dear Users, I have a couple of questions regarding Xcrysden. 1. Usually xcrysden files use the following format: PRIMVEC 5.52460788000.000.00 0.003.90648780400.00 0.000.00 19.5324384880 PRIMCOORD 14 1 31 0.3031580950 0.00-0.3114762280 31 2.6436116560 1.9532436370-1.8580462820 31 -0.0518106620 0.00-3.8817233780 31 2.7623039400 1.9532436370-5.8597314410 31 0.00 0.00-7.8129756070 31 2.7623039400 1.9532436370-9.7662192440 33 1.4763662580 1.9532436370 0.3364242780 where atomic positions are not written in crystal co-ordinates. Is it possible to specify atomic positions in crystal co-ordinates in any of .xyz or .xsf xcrysden input files (except .pwi or .pwo files). 2. How to print the thermometer in Xcrysden??? Everytime I get an error saying "could not execute /usr/bin/convert". I'll be highly obliged if anyone kindly discuss the above issues. regards, SKS JNCASR Bangalore
[Pw_forum] Xcrysden
On Fri, 2009-04-03 at 19:04 +0530, S. K. S. wrote: > Dear all, > > Thanks a lot for your kind and helpful reply. > Few things about Xcrysden are yet to be known. > > 1. Now I can print the thermometer after installing > ImageMagick. However, it prints the thermometer > separately. Please have a look on the attached file. > Is it possible in XCrysden to print the thermometer together > with the background "Xcrysden charge-density" plot This is why image manipulation or some other presentation programs are used for. Take as many "primitive" images as you like and assemble a master image there. > 2. >No! XSF uses Carthesian coordinates (Angstrom units). > > Then, is there any other smart way to change Angstrom coordinates > to crystal coordinates in Xcrysden??? The usual pen and paper > (analytical and manual) method is not always time-saving especially for > non-cubic (for instance, hexagonal) systems. There is! Instead of making XSF, make a plain pw.x input file and specify ATOMIC_POSITIONS in crystal units, then load that pw.x input file into xcrysden. Now you can pass to Carthesian if you wish so (i.e. save the loaded file as XSF). > > 3. Another thing I would like to know, whether it is possible to increase > the size of the "XYZ co-ordinate symbol" in Xcrysden??? > One can easily zoom the picture of a molecule or a crystal in the > Xcrysden and print the larger size picture because Xcrysden's print is > an XWD window dump. But what about co-ordinate symbol??? > Is it possible to make its size bigger? Unfortunately not. (you can make it manual though: print it as it is so that you will have the directions, and then make a new one in some image processing program) Regards, Tone -- Anton Kokalj J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia (tel: +386-1-477-3523 // fax:+386-1-477-3822) Please, if possible, avoid sending me Word or PowerPoint attachments. See: http://www.gnu.org/philosophy/no-word-attachments.html
[Pw_forum] Recently generated Ultrasoft PP (IMPORTANT)
Miguel Mart?nez wrote: > * Does this mean regenerating USPPs with the CVS version of ld1.x? yes > * Are there any plans to release a 4.0.5 version with more bugfixes or > will 4.1.0 be the next version? a 4.0.5 version is actually already out (without the fix). I didn't announce it because it was a sort of experiment. It is in the download page ion qe-forge.org . I think it will be the last of the series. > * Also, I suppose that multiple-projector PPs have been correctly > generated as long as rcut and rcutus are the same, right? right P. -- Paolo Giannozzi, Democritos and University of Udine, Italy
[Pw_forum] The symmetry of bands
On Fri, 2009-04-03 at 20:16 +0800, ??? wrote: > Dear dalcorso, > Thank you for your detailed reply. The initial output I posted > is not consistent with your output because I changed the > "starting_magnetization=0.00," to 0.01. Though the energy is the same, > the symmetry is different. I recalculate it with > "starting_magnetization=0.00," and the output is same as your output. > >In addition, I want to know how to calculate the exciton energy > level ? Is that possible in recent pwscf? > As far as I know the answer is no. But maybe somebody else knows better than me how to do this. Andrea > 2009/4/3 Dal Corso Andrea > > On my PC, with your input I obtain: > > &plot nbnd= 30, nks= 1 / >0.00 0.00 0.00 > -8.070 -8.070 -5.968 -5.968 1.092 1.092 6.154 > 6.154 6.169 > 6.169 > > 6.802 6.802 6.816 6.816 7.016 7.016 11.136 > 11.136 13.603 > 13.603 > 17.514 17.514 18.094 18.094 18.118 18.118 19.967 > 19.967 20.042 > 20.042 > > That compare quite well with your bands: > > &plot nbnd= 30, nks= 1 / >0.00 0.00 0.00 > -8.070 -8.070 -5.968 -5.968 1.092 1.092 6.154 > 6.154 6.169 > 6.169 > 6.803 6.803 6.816 6.816 7.015 7.015 11.136 > 11.136 13.603 > 13.603 > 17.513 17.513 18.094 18.094 18.118 18.118 19.967 > 19.967 20.042 > 20.042 > > > The output of bands.x says that the code is using the group > C_6v > to classify the bands > > xk=( 0.0, 0.0, 0.0 ) > > double point group C_6v (6mm) > there are 9 classes and 3 irreducible representations > the character table: > > E -E C22C3 -2C3 2C6 -2C6 3s_v 3s_d > -C2 -3s_v -3s_d > G_72.00 -2.00 0.00 1.00 -1.00 1.73 -1.73 0.00 0.00 > G_82.00 -2.00 0.00 1.00 -1.00 -1.73 1.73 0.00 0.00 > G_92.00 -2.00 0.00 -2.00 2.00 0.00 0.00 0.00 0.00 > > That has only three representations. An actally the .rap file > contains > only 1 2 or 3: > > &plot_rap nbnd_rap= 30, nks_rap= 1 / >0.00 0.00 0.00T > > 1 1 2 2 2 2 2 > 2 3 > 3 > 1 1 3 3 1 1 1 > 1 2 > 2 > 2 2 1 1 3 3 1 > 1 2 > 2 > > So the two bands 11-12 at 6.803 are 1 -> Gamma_7, the two > bands 13-14 at > 6.816 are 3-> \Gamma_9 and > the two bands 15-16 7.015 are 1 -> \Gamma_7. The splitting is > 13 meV and > 0.199 meV in reasonable agreement with the APL that you > mention. > > It seems that you have the correct bands but bands.x is not > using C_6v > to classify the bands. > Which is the output of bands.x? > > Andrea > > > > > On Fri, 2009-04-03 at 11:10 +0800, ??? wrote: > > Dear pwscf users, > > I calculated band structure of AlN considering > spin-orbital > > interaction. Some published reports showed that considering > > spin-orbital interaction the top of valence band is split > into the > > Gamma7, Gamma9 and Gamma7 states by crystal field and > spin-orbital > > coupling (Appl. Phys. Lett. 83, 5163). However, my > calculated band > > structure is different from the published one. The > following is the > > input files: > > scf.in > > &control > > title = 2h_aln, > > prefix = '2h_band', > > calculation = 'scf' , > > restart_mode = 'from_scratch' , > > wf_collect = .false. , > > outdir = './' , > > wfcdir = './' , > > pseudo_dir = './' , > > tstress = .true. , > > tprnfor = .true. , > >wf_collect = .true. , > > / > > &SYSTEM > >ibrav = 4, > >celldm(1) = 5.904838149212, > >celldm(3) = 1.603024550651, > > nat = 4, > >
[Pw_forum] Xcrysden
On Fri, 2009-04-03 at 17:13 +0530, S. K. S. wrote: > Dear Users, > > I have a couple of questions regarding Xcrysden. > 1. Usually xcrysden files use the following format: > > PRIMVEC > 5.52460788000.000.00 > 0.003.90648780400.00 > 0.000.00 19.5324384880 > PRIMCOORD > 14 1 > 31 0.3031580950 0.00-0.3114762280 > 31 2.6436116560 1.9532436370-1.8580462820 > 31 -0.0518106620 0.00-3.8817233780 > 31 2.7623039400 1.9532436370-5.8597314410 > 31 0.00 0.00-7.8129756070 > 31 2.7623039400 1.9532436370-9.7662192440 > 33 1.4763662580 1.9532436370 0.3364242780 > > where atomic positions are not written in crystal co-ordinates. > Is it possible to specify atomic positions in crystal co-ordinates in any > of .xyz or .xsf xcrysden input files No! XSF uses Carthesian coordinates (Angstrom units). > 2. How to print the thermometer in Xcrysden??? > Everytime I get an error saying "could not execute /usr/bin/convert". You need ImageMagick suite of programs (convert is a member of it) for "printing" in xcrysden (actually the new xcrysden version will also try to use netbpm if image-magick is missing). For ImageMagick see: http://www.imagemagick.org Note however that (probably) all linux distributions have it. So you may find the package corresponding to your distribution. Regards, Tone -- Anton Kokalj J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia (tel: +386-1-477-3523 // fax:+386-1-477-3822) Please, if possible, avoid sending me Word or PowerPoint attachments. See: http://www.gnu.org/philosophy/no-word-attachments.html
[Pw_forum] Xcrysden
On Fri, 03 Apr 2009 14:05:40 +0200, lan haiping wrote: >> 2. How to print the thermometer in Xcrysden??? >> Everytime I get an error saying "could not execute /usr/bin/convert". >> > You should install GIMP, a GNU image processor. convert is part of the ImageMagick (note the spelling!) package, not of gimp. It used to not be included in some distributions for licence/patents reasons; as far as I know most distributions include it nowadays. -- Lorenzo Paulatto SISSA & DEMOCRITOS (Trieste) phone: +39 040 3787 511 skype: paulatz www: http://people.sissa.it/~paulatto/ *** save italian brains *** http://saveitalianbrains.wordpress.com/
[Pw_forum] Recently generated Ultrasoft PP (IMPORTANT)
Dear Paolo, On Thu, 2 Apr 2009 22:14:00 +0200 Paolo Giannozzi wrote: > Just a reminder: > >* USPP generated with ld1.x may have been incorrectly written to > UPF format v.2 in all 4.0.x versions . The error may have been > small enough to go unnoticed but may be not negligible. All USPP > in UPF format tagged as version 2.0.0 should be regenerated. Excuse me for making a couple of questions: * Does this mean regenerating USPPs with the CVS version of ld1.x? * Are there any plans to release a 4.0.5 version with more bugfixes or will 4.1.0 be the next version? * Also, I suppose that multiple-projector PPs have been correctly generated as long as rcut and rcutus are the same, right? Regards, Miguel -- Miguel Mart?nez Canales Condensed Matter Physics Dpt. UPV/EHU Faculty of Science and Technology Apdo. 644 48080 Bilbao (Spain) Fax: +34 94 601 3500 Tlf: +34 94 601 5326 "If you have an apple and I have an apple and we exchange these apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas." George Bernard Shaw
[Pw_forum] Infared and Raman cross section
dynmat ! Input data (namelist "input") ! ! fildyn character input file containing the dynamical matrix !(default: fildyn='matdyn') ! q(3) realcalculate LO modes (add nonanalytic terms) along !the direction q (default: q=(0,0,0) ) ! amass(nt) realmass for atom type nt, a.u. !(default: amass is read from file fildyn) ! asr character indicates the type of Acoustic Sum Rule imposed ! - 'no': no Acoustic Sum Rules imposed (default) ! - 'simple': previous implementation of the asr used ! (3 translational asr imposed by correction of ! the diagonal elements of the dynamical matrix) ! - 'crystal': 3 translational asr imposed by optimized ! correction of the dyn. matrix (projection). ! - 'one-dim': 3 translational asr + 1 rotational asr ! imposed by optimized correction of the dyn. mat. (the ! rotation axis is the direction of periodicity; it ! will work only if this axis considered is one of ! the cartesian axis). ! - 'zero-dim': 3 translational asr + 3 rotational asr ! imposed by optimized correction of the dyn. mat. ! Note that in certain cases, not all the rotational asr ! can be applied (e.g. if there are only 2 atoms in a ! molecule or if all the atoms are aligned, etc.). ! In these cases the supplementary asr are cancelled ! during the orthonormalization procedure (see below). ! Finally, in all cases except 'no' a simple correction ! on the effective charges is performed (same as in the ! previous implementation). ! axisintegerindicates the rotation axis for a 1D system ! (1=Ox, 2=Oy, 3=Oz ; default =3) ! filout character output file containing frequencies and modes !(default: filout='dynmat.out') ! filmol character as above, in a format suitable for 'molden' !(default: filmol='dynmat.mold') ! filxsf character as above, in axsf format suitable for xcrysden !(default: filmol='dynmat.axsf') In this tutorial, i think the file sih4.cs.in is replaced by sih4.ir.in !!! 2009/4/3 jiming an > Dear PWSCF user, > I download the example of Infared and Raman cross section from > http://www.fisica.uniud.it/~giannozz/QE-Tutorial/tutorial_advph.html, and > find that in example advph.tgz the scripts of sih4.ph.in and sih4.cs.in are > missed. If someone who know how to write the script of sih4.cs.in, > please tell me, thank you. > Best Regards, > Jiming An > > > -- > ?<http://cn.rd.yahoo.com/mail_cn/tagline/card/*http://card.mail.cn.yahoo.com/> > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- Y. C. Cheng Department of Phyics Nanjing University Nanjing 210093 P. R. China Tel: 86-25-83592907 Email: yccheng.nju at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090403/658f03f4/attachment-0001.htm
[Pw_forum] The symmetry of bands
Dear pwscf users, I calculated band structure of AlN considering spin-orbital interaction. Some published reports showed that considering spin-orbital interaction the top of valence band is split into the Gamma7, Gamma9 and Gamma7 states by crystal field and spin-orbital coupling (Appl. Phys. Lett. 83, 5163). However, my calculated band structure is different from the published one. The following is the input files: scf.in &control title = 2h_aln, prefix = '2h_band', calculation = 'scf' , restart_mode = 'from_scratch' , wf_collect = .false. , outdir = './' , wfcdir = './' , pseudo_dir = './' , tstress = .true. , tprnfor = .true. , wf_collect = .true. , / &SYSTEM ibrav = 4, celldm(1) = 5.904838149212, celldm(3) = 1.603024550651, nat = 4, ntyp = 2, ecutwfc = 80, nosym = .false. , lspinorb = .true., noncolin= .true., starting_magnetization=0.00, / &ELECTRONS electron_maxstep = 100, conv_thr = 1.D-12, / ATOMIC_SPECIES N 14.00700 N.rel-pbe-rrkjus.UPF Al 26.98200 Al.rel-pbe-rrkj.UPF ATOMIC_POSITIONS (crystal) N0.3 0.7 0.379371803 N0.7 0.3 0.879371803 Al 0.3 0.7 -0.002269507 Al 0.7 0.3 0.497730493 K_POINTS automatic 4 4 4 1 1 1 band.in &control title = 2h_aln, prefix = '2h_band', calculation = 'bands' , restart_mode = 'from_scratch' , wf_collect = .false. , outdir = './' , wfcdir = './' , pseudo_dir = './' , / &SYSTEM ibrav = 4, celldm(1) = 5.904838149212, celldm(3) = 1.603024550651, nat = 4, ntyp = 2, ecutwfc = 80, occupations='fixed', nbnd=30, lspinorb = .true., noncolin= .true., starting_magnetization=0.00, / &ELECTRONS electron_maxstep = 100, conv_thr = 1.D-12, / ATOMIC_SPECIES N 14.00700 N.rel-pbe-rrkjus.UPF Al 26.98200 Al.rel-pbe-rrkj.UPF ATOMIC_POSITIONS (crystal) N0.3 0.7 0.379371803 N0.7 0.3 0.879371803 Al 0.3 0.7 -0.002269507 Al 0.7 0.3 0.497730493 K_POINTS 1 0.00 0.00 0.00 1.00 bands.in for bands.x to get band symmetry information &inputpp prefix='2h_band' outdir='./' filband='spin.dat' lsigma(3)=.true. lsym=.true. / The calculated results of the band structure at Gamma point is as following: spin.dat: &plot nbnd= 30, nks= 1 / 0.00 0.00 0.00 -8.070 -8.070 -5.968 -5.968 1.092 1.092 6.154 6.154 6.169 6.169 6.803 6.803 6.816 6.816 7.015 7.015 11.136 11.136 13.603 13.603 17.513 17.513 18.094 18.094 18.118 18.118 19.967 19.967 20.042 20.042 spin.dat.rap: &plot_rap nbnd_rap= 30, nks_rap= 1 / 0.00 0.00 0.00T 1 2 5 6 5 6 5 6 3 4 1 2 3 4 1 2 1 2 5 6 5 6 1 2 3 4 1 2 5 6 My questions are: 1. Why the calculated top of valence bands (15th, and 16th ) do not split as reported work (Appl. Phys. Lett.83,5163)? 2. In the spin.dat.rap file, what does the symbol "T" stand for? And what does the "1 2 5 6 5 6 5 ..." mean? Thank you in advance! -- Y. C. Cheng Department of Physics Nanjing University Nanjing 210093 P. R. China Tel: 86-25-83592907 Email: yccheng.nju at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090403/9a0fe047/attachment.htm
[Pw_forum] PP for Planar average of all |psi|^2
Hi Gabriele,
This is regarding the calculation of Planar Average of
|psi^2| using "PP/plan_avg.f90". So according to your suggestion I tried
this input file:
=
&inputpp
prefix='CO2',
outdir './'
filplot = 'CO2-psi-plan_avg.pot'
/
=
Before that I did SCF calculations using Gamma Kpoint.
"K_POINTS {automatic}
1 1 1 0 0 0"
With this recipe the error I got is this:
from plan_avg : error # 2
planar average with gamma tricks not yet implemented
So I can't calculate |psi^2| planar average for
k= (0.000 0.000 0.000)?
Thanks and Regards
--
SUJATA PAUL
GRADUATE STUDENT
PHYSICS DEPARTMENT
NORTH CAROLINA STATE UNIVERSITY
USA
It was written in the error message you posted at the beginning:
%%
from punch_plot : error # 1
no longer implemented, see PP/plan_avg.f90
%%
So I guessed "plot_num=9" is not implemented in post processing.
You have to use the program plan_avg.x in place of pp.x for this task.
Though I never used it, from a glance to the source I guess it should be simple
to use:
NAMELIST / inputpp / outdir, prefix, filplot
You simply need to specify these three strings...
GS
[Pw_forum] The symmetry of bands
On my PC, with your input I obtain: &plot nbnd= 30, nks= 1 / 0.00 0.00 0.00 -8.070 -8.070 -5.968 -5.968 1.092 1.092 6.154 6.154 6.169 6.169 6.802 6.802 6.816 6.816 7.016 7.016 11.136 11.136 13.603 13.603 17.514 17.514 18.094 18.094 18.118 18.118 19.967 19.967 20.042 20.042 That compare quite well with your bands: &plot nbnd= 30, nks= 1 / 0.00 0.00 0.00 -8.070 -8.070 -5.968 -5.968 1.092 1.092 6.154 6.154 6.169 6.169 6.803 6.803 6.816 6.816 7.015 7.015 11.136 11.136 13.603 13.603 17.513 17.513 18.094 18.094 18.118 18.118 19.967 19.967 20.042 20.042 The output of bands.x says that the code is using the group C_6v to classify the bands xk=( 0.0, 0.0, 0.0 ) double point group C_6v (6mm) there are 9 classes and 3 irreducible representations the character table: E -E C22C3 -2C3 2C6 -2C6 3s_v 3s_d -C2 -3s_v -3s_d G_72.00 -2.00 0.00 1.00 -1.00 1.73 -1.73 0.00 0.00 G_82.00 -2.00 0.00 1.00 -1.00 -1.73 1.73 0.00 0.00 G_92.00 -2.00 0.00 -2.00 2.00 0.00 0.00 0.00 0.00 That has only three representations. An actally the .rap file contains only 1 2 or 3: &plot_rap nbnd_rap= 30, nks_rap= 1 / 0.00 0.00 0.00T 1 1 2 2 2 2 2 2 3 3 1 1 3 3 1 1 1 1 2 2 2 2 1 1 3 3 1 1 2 2 So the two bands 11-12 at 6.803 are 1 -> Gamma_7, the two bands 13-14 at 6.816 are 3-> \Gamma_9 and the two bands 15-16 7.015 are 1 -> \Gamma_7. The splitting is 13 meV and 0.199 meV in reasonable agreement with the APL that you mention. It seems that you have the correct bands but bands.x is not using C_6v to classify the bands. Which is the output of bands.x? Andrea On Fri, 2009-04-03 at 11:10 +0800, ??? wrote: > Dear pwscf users, > I calculated band structure of AlN considering spin-orbital > interaction. Some published reports showed that considering > spin-orbital interaction the top of valence band is split into the > Gamma7, Gamma9 and Gamma7 states by crystal field and spin-orbital > coupling (Appl. Phys. Lett. 83, 5163). However, my calculated band > structure is different from the published one. The following is the > input files: > scf.in > &control > title = 2h_aln, > prefix = '2h_band', > calculation = 'scf' , > restart_mode = 'from_scratch' , > wf_collect = .false. , > outdir = './' , > wfcdir = './' , > pseudo_dir = './' , > tstress = .true. , > tprnfor = .true. , >wf_collect = .true. , > / > &SYSTEM >ibrav = 4, >celldm(1) = 5.904838149212, >celldm(3) = 1.603024550651, > nat = 4, > ntyp = 2, > ecutwfc = 80, >nosym = .false. , > lspinorb = .true., > noncolin= .true., >starting_magnetization=0.00, > / > &ELECTRONS > electron_maxstep = 100, > conv_thr = 1.D-12, > / > ATOMIC_SPECIES > N 14.00700 N.rel-pbe-rrkjus.UPF >Al 26.98200 Al.rel-pbe-rrkj.UPF > ATOMIC_POSITIONS (crystal) > N0.3 0.7 0.379371803 > N0.7 0.3 0.879371803 > Al 0.3 0.7 -0.002269507 > Al 0.7 0.3 0.497730493 > K_POINTS automatic > 4 4 4 1 1 1 > band.in > &control > title = 2h_aln, > prefix = '2h_band', > calculation = 'bands' , > restart_mode = 'from_scratch' , > wf_collect = .false. , > outdir = './' , > wfcdir = './' , > pseudo_dir = './' , > / > &SYSTEM >ibrav = 4, >celldm(1) = 5.904838149212, >celldm(3) = 1.603024550651, > nat = 4, > ntyp = 2, > ecutwfc = 80, > occupations='fixed', > nbnd=30, > lspinorb = .true., > noncolin= .true., >starting_magnetization=0.00, > / > &ELECTRONS > electron_maxstep = 100, > conv_thr = 1.D-12, > / > ATOMIC_SPECIES > N 14.00700 N.rel-pbe-rrkjus.UPF >Al 26.98200 Al.rel-pbe-rrkj.UPF > ATOMIC_POSITIONS (crystal)
[Pw_forum] Infared and Raman cross section
jiming an wrote: > in example advph.tgz the scripts of sih4.ph.in and sih4.cs.in are missed. there is a mismatch between file names cited in the tutorial and their names in the .tgz file: sih4.ph.in => sih4.nm.in sih4.cs.in => sih4.ir.in P. -- Paolo Giannozzi, Democritos and University of Udine, Italy
[Pw_forum] The symmetry of bands
> My questions are: > 1. Why the calculated top of valence bands (15th, and 16th ) do not > split as reported work (Appl. Phys. Lett.83,5163)? > 2. In the spin.dat.rap file, what does the symbol "T" stand for? And > what does the "1 2 5 6 5 6 5 ..." mean? I can reply to the second, for the moment: T is a flag, needed by plotband.x program, which identifies k-point which have a different symmetry with respect to the preceeding. It is meant to identify the special k-point in your k-point path used for plotting the bands. Since you have only one k-point in this calculation, you should not worry about this flag. The numbers on the rows are the representations to which the corresponding eigenvalues (those listed in the filband file) belong. The representations are listed in the standard output of bands.x, so that to each number you can associate an irreducible representation. GS > The calculated results of the band structure at Gamma point is as following: > spin.dat: > &plot nbnd= 30, nks= 1 / > 0.00 0.00 0.00 > -8.070 -8.070 -5.968 -5.968 1.092 1.092 6.154 6.154 > 6.169 6.169 >6.803 6.803 6.816 6.816 7.015 7.015 11.136 11.136 > 13.603 13.603 > 17.513 17.513 18.094 18.094 18.118 18.118 19.967 19.967 > 20.042 20.042 > > spin.dat.rap: > &plot_rap nbnd_rap= 30, nks_rap= 1 / > 0.00 0.00 0.00T >1 2 5 6 5 6 5 6 > 3 4 >1 2 3 4 1 2 1 2 > 5 6 >5 6 1 2 3 4 1 2 > 5 6 -- o o | Gabriele Sclauzero, PhD Student | | c/o: SISSA & CNR-INFM Democritos, | |via Beirut 2-4, 34014 Trieste (Italy) | | email: sclauzer at sissa.it | | phone: +39 040 3787 511 | | skype: gurlonotturno | o o
[Pw_forum] Choice of irreducible representations with ph.x
You are using k=0 and q=0 so the phonon code uses the gamma_gamma
tricks. The problem is that the option nrapp with gamma_gamma tricks is
not supported. In the present version of ph.x there is no input variable
to disable the gamma gamma tricks when k=0 and q=0. I have added one
variable in the cvs version.
At the moment if you really need to use the nrapp option you can disable
the gamma gamma tricks adding the instruction
lgamma_gamma=.FALSE.
after the lines:
IF (nkstot==1.OR.(nkstot==2.AND.nspin==2)) THEN
lgamma_gamma=(lgamma.AND.(ABS(xk(1,1))<1.D-12) &
.AND.(ABS(xk(2,1))<1.D-12) &
.AND.(ABS(xk(3,1))<1.D-12) )
ENDIF
in PH/phq_readin.f90 and recompile.
However the option nrapp does not produce any frequency. You have to
write a small code to collect the pieces of the dynamical matrix that
you need and to diagonalize it.
Hope this helps,
Andrea
On Thu, 2009-04-02 at 18:55 +0200, Cristian Degli Esposti Boschi wrote:
> Here follows the input file for the preliminary scf calculation
> done using pw.x:
>
> Thanks, Cristian
>
> ---
>
> &CONTROL
>calculation = "scf",
>prefix = "CoM",
>pseudo_dir = "/scratch/userinfm/cne0fm4a/pseudo/",
>outdir = "/scratch/userinfm/cne0fm4a/CoM/results/",
>verbosity= "high",
> /
> &SYSTEM
>ibrav = 0,
>celldm(1) = 1.8897261D0,
>nat = 48,
>ntyp = 5,
>ecutwfc = 100.D0,
>ecutrho = 400.D0,
>nbnd = 100,
> /
> &ELECTRONS
>electron_maxstep = 500,
>conv_thr= 1.D-6,
>mixing_beta = 0.7D0,
>diagonalization = "david",
> /
> CELL_PARAMETERS cubic
> 20.0 0.0 0.0
> 0.0 20.0 0.0
> 0.0 0.0 15.0
> ATOMIC_SPECIES
> H 1.00794 H.pbe-van_ak.UPF
> C 12.011 C.pbe-van_ak.UPF
> N 14.007 N.pbe-van_ak.UPF
> O 15.999 O.pbe-van_ak.UPF
> Fe 55.845 Fe.pbe-sp-van_ak.UPF
> ATOMIC_POSITIONS {angstrom}
> Fe 0.0 0.0 0.0 0 0 0
> N -2.015936221 0.0 0.038768204
> N -0.13925 -2.014702715 0.046905328
> N2.017269908 0.0 0.040458155
> N -0.13925 2.014652715 0.046905328
> C -2.847040814 1.101001374 0.021528526
> C -2.847040814 -1.101001374 0.021528526
> C -1.099901325 -2.845127136 0.035557609
> C1.099672879 -2.845475866 0.033358015
> C2.848427407 -1.101716959 0.018059959
> C2.848427407 1.101716959 0.018059959
> C1.099672879 2.845475866 0.033358015
> C -1.099901325 2.845127136 0.035557609
> C -2.424089030 2.424582315 0.023330214
> C -2.424089030 -2.424582315 0.023330214
> C2.424273228 -2.425359652 0.019740116
> C2.424273228 2.425359652 0.019740116
> C -4.226164834 0.682755749 0.013419289
> C -4.226164834 -0.682755749 0.013419289
> C -0.682749799 -4.225087959 0.031048576
> C0.682057949 -4.225434105 0.029188709
> C4.226987371 -0.683186680 0.002120738
> C4.226987371 0.683186680 0.002120738
> C0.682057949 4.225434105 0.029188709
> C -0.682749799 4.225087959 0.031048576
> H -3.194929270 3.196716641 0.005583502
> H -3.194929270 -3.196716641 0.005583502
> H3.194370362 -3.198147171 -0.001036024
> H3.194370362 3.198147171 -0.001036024
> H -5.076004919 1.361487055 0.008732438
> H -5.076004919 -1.361487055 0.008732438
> H -1.361920855 -5.074396365 0.029488844
> H1.360598646 -5.075191580 0.024602540
> H5.077216872 -1.361288276 -0.011051138
> H5.077216872 1.361288276 -0.011051138
> H1.360598646 5.075191580 0.024602540
> H -1.361920855 5.074396365 0.029488844
> N -0.005537284 0.0 2.101372675
> C1.071489062 0.0 2.880387333
> C -1.100816954 0.0 2.946533090
> N0.704089722 0.0 4.188705635
> C -0.674259140 0.0 4.251114030
> C -0.006438108 0.0 -1.731247148
> O -0.017672814 0.0 -2.897017310
> H -2.113804696 0.0 2.562350854
> H2.100245178 0.0 2.539608359
> H1.339496592 0.0 4.980002249
> H -1.211591117 0.0 5.192219697
> K_POINTS
> 1
> 0.0 0.0 0.0 1.0
>
>
--
Andrea Dal CorsoTel. 0039-040-3787428
SISSA, Via Beirut 2/4 Fax. 0039-040-3787528
34014 Trieste (Italy) e-mail: dalcorso at sissa.it
[Pw_forum] Nitrogen PP for spin-orbital interaction calculation
Thank you for your advice, and the N PP works fine. 2009/4/1 Dal Corso Andrea > On Wed, 2009-04-01 at 14:34 +0800, ??? wrote: > > Dear QE users, > > Recently, I try to study AlN with spin-orbital interaction. > > However,there is no N pseudopotential for relativistic calculation in > > pwscf website. Can anybody provide me such N pseudopotential or give > > me some advices to get it? Thank you in advance! > > > > atomic_doc/pseudo_library/LDA/REL/N.rel-pz-rrkjus.in<http://n.rel-pz-rrkjus.in/>or > atomic_doc/pseudo_library/PBE/REL/N.rel-pbe-rrkjus.in<http://n.rel-pbe-rrkjus.in/> > > Please use the one on the cvs version and let us know if it works. Note > that ld1.x of espresso 4.0.X has a bug in the new format so you need to > set upf_v1_format=.true. to obtain a working PP. The bug has been > corrected in ld1.x of the cvs version. > > Hope this helps, > > Andrea > > > -- > > Y. C. Cheng > > Department of Phyics > > Nanjing University > > Nanjing 210093 > > P. R. China > > Tel: 86-25-83592907 > > Email: yccheng.nju at gmail.com > > > > ___ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://www.democritos.it/mailman/listinfo/pw_forum > -- > Andrea Dal CorsoTel. 0039-040-3787428 > SISSA, Via Beirut 2/4 Fax. 0039-040-3787528 > 34014 Trieste (Italy) e-mail: dalcorso at sissa.it > > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Y. C. Cheng Department of Phyics Nanjing University Nanjing 210093 P. R. China Tel: 86-25-83592907 Email: yccheng.nju at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090403/bc6343d9/attachment.htm
[Pw_forum] Transmission calculation using PWCOND
Dear Manoj
On Wednesday 01 April 2009 22:57, Manoj Srivastava wrote:
> Dear PWSCF users and developers,
> I have been trying to understand the PWCOND code for transmission
> calculation, basically 'transmit.f90' file. The wavefunction in the left
> lead, right lead and scattering region is given by -
>
>psi_k+sum_{k'}r_{kk'}psi_k'
> psi= sum_{n} a_n psi_n+ sum_{\alpha l m} C_{\alpha l m}psi_{\alpha l m}
>sum_{k'}t_{kk'}psi_k'
>
> The above expression is from Choi & Ihm's paper, on which I believe PWCOND
> is based on. Now undetermined coefficients in above expression are
> r_{kk'}, a_n, C_{\alpha,l,m}, t_kk'. I am confused on code evaluates these
> coefficients. My understanding is you first get the wavefunction in the
> leads and then solve scattering region the same way to get the
> wavefunction in scattering region, so at this point you have already
> determined a_n and C_{\alpha,l,m}. At last do boundary matching condition
> between leads and scattering region to get reflection and transmission
> coefficient. Am I right?
No, the scattering state (SS) is completely determined by unknown
coefficients which are: {r_kk', a_n, a_alpha, t_kk'}, the first defines the
SS in the left lead, the two next in the scattering region, and the last one
in the right lead. What you have found before are just basis solutions phi_n
and phi_alpha of the Sroedinger eq. in the scattering region over which you
expand the SS with coefficients (unknown yet) a_n and a_alpha.
Hope this helps,
Alexander
> My thinking is based on simple quantum mechanics
> scattering problem where we solve schrodinger's equation in each region
> and then do boundary matching to get reflection and transmission
> coefficients.
>
> Now looking at the subroutine 'transmit.f90', this does not appear to be
> the case. It seems as if we are solving the Schrodinger's equation in the
> scattering region and doing boundary matching at the same time. Using a
> big matrix and solving something like AX=B. Would anybody mind explaing
> what's going on in subroutine transmit.f90?
>
> Regards,
> Manoj Srivastava
> Physics Graduate Student
> University Of Florida, Gainesville, FL
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
[Pw_forum] Infared and Raman cross section
Dear PWSCF user, I download the example of Infared and Raman cross section from http://www.fisica.uniud.it/~giannozz/QE-Tutorial/tutorial_advph.html, and find that in example advph.tgz the scripts of sih4.ph.in and sih4.cs.in?are missed.?If someone who know how to write?? the script of sih4.cs.in, please?tell me, thank you. Best Regards, Jiming An ___ ? http://card.mail.cn.yahoo.com/ -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090403/1a0f7fb7/attachment.htm
[Pw_forum] Ti
Dear paolo For valence in LDA thanks --- On Thu, 4/2/09, Paolo Giannozzi wrote: From: Paolo Giannozzi Subject: Re: [Pw_forum] Ti To: "PWSCF Forum" Date: Thursday, April 2, 2009, 10:16 AM On Apr 1, 2009, at 21:39 , ali kazempoor wrote: Has anyone Ti pseudopotential in norm-conserving format? with semicore electrons in core or in valence? for which XC functional? Paolo --- Paolo Giannozzi,?Democritos and?University of Udine, Italy -Inline Attachment Follows- ___ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090403/13801d4a/attachment.htm
[Pw_forum] Possible reason for "ortho went bananas"
Zhiping Xu wrote: > Dear all: > I performed a calculation using cp.x. However I always get "ortho > went bananas" errors either using calculation = 'scf' or 'cp'. Previous > post on this issue says it's convergence problem. My system converges > well using pw.x. I totally have no idea about this bananas error, can > someone help me on this? Thanks. > Best, > ZP At the very beginning, dt needs to be small - a few steps with dt=5 or so would be good - this is because the initial random wavefunctions change a lot in the first steps. Also, your script has bot ionic dynamics and damped electronic dyanmics; this is not a car-parrinello procedure. Suppose you want to do a real cp run, this is what you need to do: a few electronic steps with ions fixed, small dt (1 to 5) to let the random wavefunctions get reasonable in shape. ~100 elecronic steps with ions fixed, and either damped electronic dynamics or conjugate gradients minimization, to let the electrons converge very weel to their ground state. start the cp runs, with verlet dynamics on the ions and on the electrons. To become expert with the stuff, do not use any thermostat at first - thus you can see how your electronic and ionic energy go. dt at most 10, probably small. There are few videos on the web (linked from the page) with lectures on ab-initio md (mostly by me, not that I am the most qualified person on the topic). What is your system, also ? A carbon dimer ? A carobn chain ? why the other pseudos ??? Note tha tthe carbon dimer is a "metal", since as it vibrates it has level crossings between homo and lumo - the only way to deal with it is with a direct minimization (in cp there is something called ensemble-dft, not too tested, thought). Please read more on the cp method (e.g. the online paper by Hutter and Marx) before continuing. Once used properly, it does work extremely well. nicola -- - Prof Nicola Marzari Department of Materials Science and Engineering 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu
