Sorry, in my previous e-mail I have mistaken the concept. Actually pseudopotentials are built to fit to a good approximation the all-electron energy levels of the valence electrons. What would be different is the total energy of the system. Anyway, the problem of self-interaction will remain, and I doubt that you could get exactly 1 Ry.
GS Gabriele Sclauzero wrote: > Dear Dimpy, > > Dimpy Sharma wrote: >> Hi there, >> I tried to calculate the ground state energy for isolated hydrogen atom >> with the following input,however I got the fermi energy level at >> -3.5661eV, while it should be -13.6eV. > > I think that in your calculation, the Fermi level will be approximatively > equal to the 1s > electron energy level. You should be aware that you are using a > pseudopotential code: even > in the case of a one electron system you won't get something close to the > true energy of > the 1s level of the hydrogenoid atom unless you use an all-electron formalism > (maybe PAW > can give a n AE energy estimate). > Anyway, another big problem here is the self-interaction error. Even an AE > calculation > would give you a not so good value, I suspect. > Maybe you can get something close to the experimental energy level by using > ld1.x (as Lihn > suggested) and enabling the self-interaction correction (see > Doc/INPUT_LD1.txt). > Besides all this, I believe that in general it is better to use fixed > occupations from > input, rather than smearing, in atomic calculations with pw.x. > > HTH > > GS > >> &CONTROL. >> calculation ='scf' >> restart_mode = 'from_scratch' >> outdir = '/sfiwork/dsharma/eigenvaluesSi/wf_H/' >> pseudo_dir = '/sfiwork/dsharma/QE_Pseudos/' >> prefix = 'H' >> tstress = .true. >> tprnfor = .true. >> wf_collect =.true. >> / >> &SYSTEM >> ibrav = 1 >> celldm(1) = 15 >> nat = 1 >> ntyp = 1 >> ecutwfc = 40 >> ecutrho = 160.0 >> nbnd = 2, >> nspin=2, >> starting_magnetization(1)=0.5 >> nosym=.true., >> occupations='smearing', >> smearing='mp', >> degauss=0.01, >> >> / >> &ELECTRONS >> diagonalization ='cg' >> mixing_mode = 'local-TF' >> conv_thr = 1.0d-6 >> mixing_beta = 0.7 >> / >> ATOMIC_SPECIES >> H 1.00794 H.pz-vbc.UPF >> ATOMIC_POSITIONS angstroms >> H 0.0000 0.0000 0.0000 >> K_POINTS automatic >> 1 1 1 0 0 0 >> >> Thanks >> >> Dimpy >> UCC >> Ireland >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> 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
