Hi Zhu, The Fermi energy (and the Kohn-Sham eigenvalues for that matter) found in the output file are referenced specifially to the potential for the calculation. So to recover the 4~5 eV that you are expecting you need to determine the vacuum potential.
hope that helps, Nicholas On Thu, 10 Jan 2008, Zhu Xi wrote: > Hi Nicholas, > thanks for your reply, but to my understaning, the 0.625eV fermi energy is > wrong, it should be between -5~-4eV, I don't know why the code give such a > fermi energy..... > > > On 1/10/08, Nicholas E. Singh-Miller <nedward at mit.edu> wrote: >> >> Dear Zhu Xi, >> >> I have not run your input file, but assuming that it is correct and this >> 0.625eV is what you read directly from the output, this Fermi energy >> should also be correct. If you are interested in the work function of >> the (3,3)CNT you will have to obtain the difference between a vacuum >> potential and the Fermi energy. In short the potential in the vacuum != 0 >> due to the use of periodic boundary conditions. If you use pp.x to >> obtain the potential remember that is is output in Rydbergs. This is all >> discussed other times on the forum. >> >> best of luck, >> >> Nicholas >> >> On Thu, 10 Jan 2008, Zhu Xi wrote: >> >>> Dear users, >>> >>> I run a scf calculation of (3,3)CNT, but the fermi energy is 0.652eV, >> can >>> anyone give some suggestion? thanks >>> >>> >> ==================================================================================== >>> >>> &control >>> calculation='scf', >>> PSEUDO_DIR='./', >>> prefix='33', >>> forc_conv_thr=1.0D-4, >>> / >>> &SYSTEM >>> ibrav = 0, >>> celldm(1)= 18.8972612499, >>> nat = 12, >>> ntyp = 1, >>> ecutwfc = 40.0 , >>> nosym = .true. , >>> nbnd = 48 , >>> occupations= 'smearing',degauss = 0.001 >>> >>> / >>> &electrons >>> conv_thr = 1.D-6, >>> mixing_beta = 0.5D0, >>> / >>> CELL_PARAMETERS >>> 1.0 0.000000000 0.000000000 >>> 0.000000000 1.0 0.000000000 >>> 0.000000000 0.000000000 0.245951 >>> ATOMIC_SPECIES >>> C 12.00000 C.pz-vbc.UPF >>> ATOMIC_POSITIONS (crystal) >>> C 0.625289967 0.669611155 0.250000000 >>> C 0.487077242 0.709466388 0.250000000 >>> C 0.291384631 0.523168925 0.250000000 >>> C 0.374710033 0.330388845 0.750000000 >>> C 0.512922758 0.290533612 0.750000000 >>> C 0.708615369 0.476831075 0.750000000 >>> C 0.416429985 0.692001578 0.750000000 >>> C 0.675464001 0.616817067 0.750000000 >>> C 0.312292454 0.592869751 0.750000000 >>> C 0.583570015 0.307998422 0.250000000 >>> C 0.324535999 0.383182933 0.250000000 >>> C 0.687707546 0.407130249 0.250000000 >>> K_POINTS automatic >>> 1 1 11 0 0 0 >>> >>> ================================================== >>> >> >> ***************************************** >> Nicholas E. Singh-Miller >> Ph.D. Candidate >> Prof. Marzari Group (quasiamore.mit.edu) >> Materials Science and Engineering >> Massachusetts Institute of Technology >> 13-4066 >> (617)324-0372 >> ***************************************** >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum >> > > > > ***************************************** Nicholas E. Singh-Miller Ph.D. Candidate Prof. Marzari Group (quasiamore.mit.edu) Materials Science and Engineering Massachusetts Institute of Technology 13-4066 (617)324-0372 *****************************************
